948 lines
39 KiB
Plaintext
948 lines
39 KiB
Plaintext
Newsgroups: rec.radio.amateur.digital.misc,rec.radio.info,rec.answers,news.answers
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Path: bloom-beacon.mit.edu!nic.hookup.net!paladin.american.edu!howland.reston.ans.net!cs.utexas.edu!swrinde!sgiblab!wattres!news
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From: steve@wattres.SJ.CA.US (Steve Watt -- KD6GGD)
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Subject: rec.radio.amateur.digital.misc Frequently Asked Questions
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Message-ID: <digital-faq-1-759557969@wattres.SJ.CA.US>
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Reply-To: digital-faq@wattres.SJ.CA.US (Digital Amateur Radio FAQ Coordinators)
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Followup-To: rec.radio.amateur.digital.misc
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Organization: Steven Watt, Consultant San Jose, CA, USA
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Approved: news-answers-request@MIT.Edu,rec-radio-info@ve6mgs.ampr.ab.ca
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Expires: Tue 01 Mar 94 20:19:29 GMT
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Supersedes: <digital-faq-1-756552901@wattres.SJ.CA.US>
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Summary: Common quesions and answers about Digital Amateur Radio.
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Keywords: FAQ Amateur Radio HAM packet digital
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Date: Wed, 26 Jan 94 04:19:35 GMT
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Lines: 930
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Xref: bloom-beacon.mit.edu rec.radio.amateur.digital.misc:1896 rec.radio.info:4036 rec.answers:3863 news.answers:14527
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Posted-By: auto-faq 3.1.1.4
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Archive-name: radio/ham-radio/digital-faq
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Frequently Asked Questions for Digital Amateur Radio
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(Well, it's still mostly just packet...)
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$Id: packet-faq.1,v 1.4 1994/01/26 04:18:23 steve Exp $
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This document is for unlimited distribution.
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Please send corrections and additions to:
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digital-faq@wattres.sj.ca.us
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Which will expand to a list of people who are familiar with most digital
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issues. I hope. ;-)
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The Digital Radio FAQ list will be posted on a monthly basis to
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rec.radio.amateur.digital.misc, rec.radio.info, rec.answers, and news.answers.
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The current version of this document is available via anonymous FTP at
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ftp.cs.buffalo.edu.
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Many FAQ's, including this one, are available on the archive site
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rtfm.mit.edu in the directory pub/usenet/news.answers. The name under
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which a FAQ is archived appears in the Archive-Name: line at the top
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of the article. This FAQ is archived as radio/amateur/digital-faq.
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There is also a mail server on rtfm.mit.edu, which can be addressed as
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mail-server@rtfm.mit.edu. For details on how to operate this server,
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send a message to that address with the word "help" in the BODY of the
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message.
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Table of contents:
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1 Basic Packet Radio Information
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1.1 What is packet radio?
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1.2 What is amateur radio?
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1.3 What can I do on packet radio?
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1.4 Why packet over other digital modes?
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1.5 What elements make up a packet station?
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TNC (Terminal Node Controller)
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Computer or Terminal
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A radio
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1.6 What do you mean we can all use the same channel?
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1.7 What is AX.25 ?
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1.8 What is RTTY ?
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1.9 What is AMTOR ?
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1.10 Definitions: Commonly used terms in Amateur Packet Radio
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1.11 Do's and Don'ts : Rules and Regulations
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2 Computing Network Resources for Amateur Digital radio
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2.1 What Newsgroups/mailing lists are available?
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2.2 What anonymous FTP sites and mail servers are available?
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2.3 How do I contact the ARRL through email?
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2.4 Are there any gateways for mail or news
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2.4.1 The W2XO Internet mail <-> packet mail gateway
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2.4.2 The N0ARY Internet mail <-> full packet BBS gateway
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2.4.3 The N6QMY Internet mail <-> full packet BBS gateway
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2.4.4 LAN Gateways (Packet wormholes via Internet)
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2.5 How do I contact TAPR?
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3 Networking and special packet protocols
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3.1 Are there any other protocols in use other than AX.25?
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3.2 What is TCP/IP?
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3.3 How do I get an IP address?
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3.4 Networking Schemes
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What are some of those other networking schemes?
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Digipeaters
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KA-Nodes
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NET/ROM
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ROSE
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3.5 BBS message transfer
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1 Basic Packet Radio Information
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1.1 What is packet radio?
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Packet radio is one method of digital communications via amateur radio.
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Packet radio takes any digital data stream and sends that via radio to
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another amateur radio station. Packet radio is so named because it sends
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the data in small bursts, or packets.
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1.2 What is amateur radio?
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Amateur Radio (sometimes called Ham Radio) is individuals using
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specified radio frequencies for personal enjoyment, experimentation,
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and the continuation of the radio art. Amateur radio operators must be
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licensed by their government. In the United States, the Federal
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Communications Commission issues amateur radio licenses. Normally, a
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test on operating practices, radio theory, and in some cases Morse code
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proficiency test is administered. Amateur radio is not to be used for
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commercial purposes. Also, amateur radio operators are restricted from
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using profanity and using amateur radio for illegal purposes.
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For more information on Amateur Radio in general, see the monthly
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frequently asked questions (FAQ) posting in rec.radio.amateur.misc. A
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copy of that FAQ is also available for FTP from ftp.cs.buffalo.edu and
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by mail from rtfm.mit.edu.
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1.3 What can I do on packet radio?
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Keyboard-to-Keyboard contacts:
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Like other digital communications modes, packet radio can be used to
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talk to other amateurs. For those who cannot use HF frequencies, two
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amateurs can talk to each other from long distances using the packet
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radio network.
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Packet BBS operations:
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Many cities have one or more packet Bulletin Board System (BBS) available
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on the local packet network. Amateurs can check into the BBSes and read
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messages from other packet users on almost any topic. BBSes are
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networked together over the packet network to allow messages to reach a
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broader audience than just your local BBS users. Private messages may also
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be sent to other packet operators, either locally or who use other
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BBSes. BBSes have the latest ARRL, AMSAT, and propagation bulletins.
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Many BBSes have a file section containing various text files full of
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information on amateur radio in general.
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DX Packet Cluster:
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A recent development is use of packet radio for DX spotting. HF
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operators connect to the local DX Packet Cluster for the latest reports
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on DX. Often a user will 'spot' some hot DX and distribute the DX
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report real time.
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File Transfer:
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With special software, amateurs can pass any binary files to other
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amateurs. Currently, this is done with TCP/IP communications, YAPP,
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and other specialized protocols.
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Satellite Communications:
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Many of the amateur radio satellites contain microcomputer systems that
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can provide special information to amateurs. Some satellites contain
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CCD cameras on board and you can download images of the earth and the
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stars. Others provide store and forward packet mailboxes to allow
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rapid message transfers over long distances. Some satellites use
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AX.25, some use special packet protocols developed for satellite
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communications. A few transmit AX.25 packets over FM transmitters, but
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most use SSB transmissions.
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1.4 Why packet over other digital modes?
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Packet has three great advantages over most of the other digital modes:
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transparency, error correction, and automatic control.
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The operation of a packet station is transparent to the end user;
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connect to the other station, type in your message, and it is sent
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automatically. The Terminal Node Controller (TNC) automatically
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divides the message into packets, keys the transmitter and sends the
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packets. While receiving packets, the TNC automatically decodes,
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checks for errors, and displays the received messages. In addition,
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any packet TNC can be used as a packet relay station, sometimes called a
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digipeater. This allows for greater range by stringing several packet
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stations together.
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Packet radio provides error free communications because of built in
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error detection schemes. If a packet is received, it is checked for
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errors and will be displayed only if it is correct.
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With VHF/UHF packet, many countries allow packet operators to operate
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in automatic control mode. This means that you can leave your packet
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station on constantly. Other users can connect to you at any time they
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wish to see if you are home. Some TNC's even have Personal BBSes
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(sometimes called mailboxes) so other amateurs can leave you messages
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if you are not at home.
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The most important advantage of packet over other modes is the ability
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for many users to be able to use the same frequency channel simultaneously.
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No other digital mode yet gives this ability.
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1.5 What elements make up a packet station?
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TNC (Terminal Node Controller): A TNC contains a modem, a CPU, and the
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associated circuitry required to convert between RS-232 and the packet
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radio protocol in use. It assembles a packet from some of the data on
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the serial line, computing an error check (CRC) for the packet, modulates
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it into audio frequencies, and puts out appropriate signals to transmit
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that packet over the connected radio. It also reverses the process,
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translating the audio that the connected radio receives into a byte
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stream on the RS-232 port.
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Most TNC's currently use 1200 BPS (bits per second) for local VHF and UHF
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packet, and 300 BPS for longer distance, lower bandwidth HF
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communication. Higher speeds are available for use in the VHF, UHF, and
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especially microwave region, but they often require unusual hardware and
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drivers.
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Computer or Terminal: This is the user interface. A computer running a
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terminal emulator program, a packet-specific program, or just a dumb
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terminal can be used. For computers, almost any phone modem communications
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program can be adapted for packet use, but there are also customized packet
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radio programs available.
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A radio: For 1200 BPS UHF/VHF packet, commonly available narrow band FM
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voice radios are used. For HF packet, 300 BPS data is used over
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single side band modulation. For high speed packet (anything greater
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than 1200 BPS), special radios or modified FM radios must be used.
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1.6 What do you mean we can all use the same channel?
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Packet radio uses a protocol called AX.25. AX.25 specifies channel
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access (ability to transmit on the channel) to be handled by CSMA
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(Carrier Sense Multiple Access). If you need to transmit, your TNC
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monitors the channel to see if someone else is transmitting. If no one
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else is transmitting, then the TNC keys up the radio, and sends its
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packet. All the other stations hear the packet and do not transmit
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until you are done. Unfortunately, 2 stations could accidentally
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transmit at the same time. This is called a collision. If a collision
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occurs, neither TNC will receive a reply back from the last packet it
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sent. Each TNC will wait a random amount of time and then retransmit
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the packet.
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In actuality, a more complex scheme is used to determine when the TNC
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transmits. See the "AX.25 Protocol Specification" for more
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information.
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1.7 What is AX.25?
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AX.25 (Amateur X.25) is the communications protocol used for packet
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radio. A protocol is a standard for how two computer systems are to
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communicate with each other, somewhat analogous to using business format
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when writing a business letter. AX.25 was developed in the 1970's and
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based of the wired network protocol X.25. Because of the difference in
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the transport medium (radios vs. wires) and because of different
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addressing schemes, X.25 was modified to suit amateur radio's needs.
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AX.25 includes a digipeater field to allow other stations to
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automatically repeat packets to extend the range of transmitters. One
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advantage of AX.25 is that every packet sent contains the sender's and
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recipient's amateur radio callsign, thus providing station identification
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with every transmission.
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1.8 What is RTTY?
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RTTY (Radio TeleTYpe) is one of the more common communications protocols
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used in the HF bands. It is a half-duplex, non error-correcting mode that
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can be used by any number of stations on a frequency in a round-table
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fashion. Note that transmit/receive switching is manual, so all parties
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in a roundtable need to agree on who transmits next. It is primarily used
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for single keyboard-to-keyboard contacts. RTTY uses Baudot character
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encoding (also known as ITA2), which is a 5 bit code. Those who can do
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advanced math ;) will note that 5 bits is only 32 possible combinations,
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which is not enough for a full alphanumeric set, much less mixed-case
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alphabetics. Baudot (and RTTY) gets around this limitation by defining
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two "shifts" which switch between a "letters case," and a "figures case."
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On older RTTY setups (ones which actually use a teletype, for instance),
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you have to worry about the letters/figures shift. However, most TNCs and
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multimode digital controllers now do the "Right Thing(TM)" with respect to
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those shift characters, sending them as necessary for the data being
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transmitted. Lower case is not used on Baudot RTTY. ASCII can be used
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in RTTY as well, but it is very uncommon.
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1.9 What is AMTOR?
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AMTOR (AMateur Teleprinting Over Radio) is an error-correcting protocol
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used in the HF bands. It uses the same character set as Baudot (ITA2),
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but is encoded differently, so that each character has a constant mark
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to space ratio. This constant ratio is how errors are detected. Errors
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are corrected via either of two methods: ARQ (Automatic Retransmit
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reQuest), and FEC (Forward Error Correction).
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In ARQ mode, exactly two stations connect to each other. The station
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with data to transmit (also known as the Information Sending Station, or
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ISS) transmits 3 characters, and then waits for the other station (called
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the Information Receiving Station, or IRS) to send back an acknowledgment
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that those 3 characters were correctly received. This back-and-forth
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activity makes for the characteristic "chirp-chirp-chirp" of AMTOR ARQ
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operation. This also means that each transceiver needs to be able to
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switch from sending to receiving mode fairly quickly. The first time
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that you operate AMTOR ARQ with a relay-switched rig, you will be
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convinced that the rig is going to self-destruct. ;)
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In FEC mode, one station can communicate with many others at once, since
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there is no back-and-forth acknowledging of data. FEC gets its error
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correction from time diversity, which is a fancy way of saying it sends
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each character twice. Actually, it interleaves the characters, so that
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the character is not repeated until 4 character times later. An example:
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The text string to send is "This is FEC."
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What comes out of the controller looks like "ThisThisis Fis FEC._EC._"
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The receiving controller looks for which of the characters have a proper
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mark to space ratio, and prints the one that does. If neither do,
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it prints an error symbol.
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1.10 Definitions: Commonly used terms in Amateur Packet Radio
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44 net - The class A network designator for TCP/IP amateur packet
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radio. All numerical TCP/IP addresses on packet radio should be in the
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format 44.xxx.xxx.xxx.
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AFSK - Audio Frequency Shift Keying. A method of representing
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digital information by using different audio frequencies modulated on
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a carrier.
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AMPR - Amateur Packet Radio.
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ampr.org - The high level domain recognized on Internet for amateur
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packet radio TCP/IP.
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AMTOR - AMateur Teleprinting Over Radio. This protocol allows error-free
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point-to-point or multicast, single user per channel communications. Usually
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used on HF, but not VHF or above.
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ARQ - Automatic Resend reQuest. This is the point-to-point error correcting
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mode for AMTOR. It works by sending bursts of 3 characters, and then the other
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station sends an OK/NotOK code for those 3 characters.
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AX.25 - Amateur X.25 protocol. The basis of most packet systems.
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See section 1.7 for more information.
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CRC - Cyclic Redundancy Check. The error detection scheme included
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in each packet. Verify that the packet was received error free.
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CSMA - Carrier Sense Multiple Access. A system allowing many
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stations to use the same radio frequency simultaneously for packet
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communications.
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digi - Short name for a digipeater
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digipeater - A packet radio station used for repeating packets. See
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section 3.3.1 for more information.
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FCC - Federal Communications Commission. Regulates and issues
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licenses for amateur radio in the United States.
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FEC - Forward Error Correction. This is the multicast method of (almost)
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error-corrected communications on AMTOR. It works by sending each character
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twice.
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FM - Frequency Modulation. The radio modulation scheme used for VHF
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and UHF packet communications.
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FSK - Frequency Shift Keying. A method of representing digital
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information by shifting the radio carrier frequency different amounts
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to represent ones and zeros.
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HDLC - (High-Level Data Link Control Procedures) A standard for high
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level link control. (ISO 3309)
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KA9Q NOS - (KA9Q Network Operating System) A TCP/IP program
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originally developed by Phil Karn, KA9Q. Currently there are many
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different versions available. See section 3.2 for more information.
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KA-Node - A simple networking scheme developed by TNC maker
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Kantronics. See section 3.3.2 for more info.
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KISS - Keep It Simple Stupid. A simple interface developed for
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communications between TNCs and computers. This allows for most of
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the packet processing to be handled by the computer. Commonly used
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with packet TCP/IP software.
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LAN - Local Area Network. A packet network developed for
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communications throughout a city or region. Often, the LAN uses
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separate frequencies from inter-city packet links.
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modem - MODulator/DEModulator. Converts the analog signals into
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a binary data stream (a series of ones and zeros) for the TNC or a
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micro-computer. First step in decoding packets. It also converts
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binary data to analog, which is the last step in encoding packets.
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NET/ROM - A scheme for packet radio networking. See section 3.3
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for more information.
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NODE - A network node. Often a network node running NET/ROM.
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PPP - Point to Point Protocol. PPP is another protocol used for moving
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IP frames over a serial line. It supports host authentication, and non-
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transparent serial lines. It also has a standard way of negotiating
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header (and potentially data) compression over the line. See also SLIP.
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protocol - A standard used for intercommunication between different
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computer systems.
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RS-232 (RS-323C) - A (more or less) standard for interconnection of
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serial peripherals to small computer systems. In packet radio,
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RS-232 is the most common interface between TNC's and the
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Computer/Terminal.
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RTTY - Radio TeleTYpe. This protocol allows point-to-point or multicast,
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single user per channel communications, without error correction.
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SLIP - Serial Line Internet Protocol. A trivial protocol for putting
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IP frames over a serial line to do (potentially) cheap TCP/IP networking.
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Approximately the same as KISS, except over wireline networks. See also
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PPP.
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SSB - Single Side Band. The radio modulation scheme used for HF packet
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and satellite packet communications.
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TAPR - Tucson Amateur Packet Radio. Was the first group to create a
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packet radio TNC using AX.25. Soon a TAPR TNC became cloned by many
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others. TAPR continues development of packet radio equipment.
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TCP/IP - Transmission Control Protocol/Internet Protocol. A set of
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utility programs used over AX.25. See sections 3.2 for more
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information.
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TNC - Terminal Node Controller. See section 1.5 for more
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information.
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1.12 Do's and Don'ts : Rules and Regulations
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NOTE: These regulations apply only to amateurs regulated by the FCC
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(United States), but often are similar to regulations in other
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countries.
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[Since I have no experience with amateur radio in other countries, I
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cannot make any comments. Please bring any notable exceptions to my
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attention. -ed]
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Although there are no specific rules that apply to amateur packet
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radio, the general amateur radio rules force some restrictions on
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packet usage.
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Can I set up a TNC at home and one at work so I can check my
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Electronic mail via packet?
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This cannot be done without special restrictions. Amateur radio
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rules prohibit any business. Since you could have mail from your
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boss (or maybe even someone selling you something over Internet),
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that would constitute business activity and is specifically
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prohibited.
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Profanity can also be a complication. Since you have no control over
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the language used in E-mail, proper filtering is required. Since no
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filter scheme can catch every offense, it is best to say every
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message must be hand filtered.
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I would like to set up a packet radio gateway between a land line
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computer network and the packet network. Is this possible?
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Yes, and there are several such gateways in use, but they must be
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managed with caution. Electronic mail may be passed FROM the packet
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|
network INTO the land line network without intervention. However,
|
|
mail passed TO packet radio is considered third party traffic (the
|
|
sender is not an amateur) and these messages must be hand filtered to
|
|
ensure that rules of message content are followed.
|
|
|
|
|
|
It's my license if I use packet radio illegally anyway, so what does
|
|
anyone else care!?
|
|
|
|
Packet radio is one of the few NETWORKED systems in amateur radio.
|
|
Many people have helped develop the network and there are many
|
|
amateurs who own parts of the packet radio network. Sending packet
|
|
BBS mail, digipeating, and sharing the channel involves the licenses
|
|
of MANY people. Because of FCC rules stating that anything to come
|
|
out of a transmitter (either in automatic mode or via your direct
|
|
control) is the licensee's responsibility, one illegal message sent
|
|
over the packet radio network could literally jeopardize the licenses
|
|
of thousands of other amateurs. When in doubt, it is best to check
|
|
with other amateurs about sending the message before it is sent.
|
|
|
|
|
|
I have some ideas on how to use packet radio in a new way, but I
|
|
don't know if it is legal. Who could tell me if I can do it
|
|
legally?
|
|
|
|
The worst thing you can do is talk to the FCC about such an issue. The
|
|
FCC rules are written to be general enough to encompass but not
|
|
restrict new radio activities. In the past, any non-thought-out
|
|
requests sent to the FCC have meant a reduction of privilege for all
|
|
amateur radio operators.
|
|
|
|
The best source for legal assistance is your national amateur radio
|
|
association. In the United States, that is the American Radio Relay
|
|
League (ARRL). Another good place for such conversations is over
|
|
Usenet/packet mailing lists, or the amateur radio BBS network.
|
|
|
|
|
|
2 Computing Network Resources for Amateur Packet radio
|
|
|
|
This section summarizes the resources available on Internet for amateur
|
|
packet radio operators.
|
|
|
|
|
|
2.1 What Newsgroups/mailing lists are available?
|
|
|
|
This is a list of all groups that regularly discuss amateur packet
|
|
radio. For newsgroups, join the group through use of your news
|
|
reader. For mailing lists, add a '-request' to the end of the list
|
|
name to request subscriptions. For listserv groups, send mail to
|
|
'listserv' at the node which contains the list. The first line of the
|
|
mail should be 'SUBSCRIBE groupname yourname'. Send the command 'help'
|
|
for more information.
|
|
|
|
rec.radio.amateur.packet (Newsgroup): General discussions involving
|
|
Packet Radio. This group was deleted on 21 September 93!
|
|
|
|
rec.radio.amateur.digital.misc (Newsgroup): General discussions about
|
|
all aspects of digital transmissions over Amateur Radio. This group
|
|
is a replacement for rec.radio.amateur.packet.
|
|
|
|
rec.radio.amateur.equipment (Newsgroup): May contain discussions about
|
|
equipment related to digital amateur radio, specifically HF rigs that
|
|
are good for HF digital modes, and the like.
|
|
|
|
rec.radio.amateur.homebrew (Newsgroup): Contains discussions on making
|
|
your own gear, which includes packet, AMTOR, and RTTY equipment.
|
|
|
|
rec.radio.amateur.misc (Newsgroup): General amateur radio discussion.
|
|
Usually does not contain any particular information about Digital
|
|
Amateur Radio.
|
|
|
|
rec.radio.amateur.policy (Newsgroup): Discussion of regulation
|
|
policies regarding every aspect of amateur radio. Occasionally deals
|
|
with policies of packet coordination and legal issues of packet radio.
|
|
|
|
rec.radio.swap (Newsgroup): General For-Sale for any radio equipment.
|
|
Occasionally will have packet equipment for sale. Recommended location
|
|
for any amateur packet radio for-sale items.
|
|
|
|
info-hams@ucsd.edu (Listserv group): A digest redistribution of the
|
|
rec.radio.amateur.misc Usenet discussion.
|
|
|
|
packet-radio@ucsd.edu (Listserv group): General discussions involving
|
|
packet radio and packet-related issues.
|
|
|
|
ham-digital@ucsd.edu (Listserv group): A digest redistribution of the
|
|
rec.radio.amateur.digital.misc Usenet discussion.
|
|
|
|
ham-policy@ucsd.edu (Listserv group): A digest redistribution of the
|
|
rec.radio.amateur.policy Usenet discussion
|
|
|
|
hs-modem@wb3ffv.ampr.org (Mailing list): Discussion of high speed
|
|
modems and radios available and future plans. Also includes discussion
|
|
of networking using high speed modems. This list is not very active.
|
|
|
|
tcp-group@ucsd.edu (Mailing list): Group discussion of technical
|
|
developments of TCP/IP over packet radio and use of the NOS TCP/IP
|
|
programs.
|
|
|
|
gateways@uhm.ampr.org (Mailing list): Discussion of current gateways
|
|
and future plans for gateways. May deal with sensitive internetworking
|
|
issues.
|
|
|
|
listserv@knuth.mtsu.edu has several interesting mailing lists available:
|
|
|
|
GRAPES-L Discussions with GRAPES (Georgia Radio Amateur
|
|
Packet Enthusiasts Society) on 56kb WAN's and
|
|
the WA4DSY 56kb RF modem that they distribute.
|
|
|
|
TENNET-L Tennessee's efforts at a coordinated high-speed
|
|
RF packet network
|
|
|
|
GRACILIS-L Discussions on Gracilis tcp/ip packet equipment.
|
|
Includes some of the people from Gracilis.
|
|
|
|
KA9Q-UNIX Discussions on porting and using various versions
|
|
of KA9Q Unix/Xenix NET/NOS under any of a variety
|
|
of Unix/Xenix variants.
|
|
|
|
TNV-HAMS General discussions among email connected
|
|
amateur radio operators in and surrounding
|
|
Tennessee
|
|
|
|
Send a message with a body of "HELP" to get help from the list server. Also,
|
|
Internet users may now INTERACTIVELY work with the Listserv there by:
|
|
|
|
telnet knuth.mtsu.edu 372
|
|
|
|
or
|
|
|
|
telnet 161.45.1.1 372
|
|
|
|
|
|
For all lists at ucsd.edu, archives may be found via anonymous FTP at
|
|
ucsd.edu. Some listserv groups also have archives. Send the command
|
|
'help' to the group's listserv for more information. Digest mailings
|
|
for the ucsd.edu discussions are also available. Send mail to
|
|
listserv@ucsd.edu with the first line being 'longindex' for more
|
|
information.
|
|
|
|
Terry Stader (KA8SCP) <tstader@aol.com> maintains a list of Mac
|
|
packet-related software, and posts it periodically (somewhat less often
|
|
than monthly) to rec.radio.amateur.digital.misc.
|
|
|
|
Carl Trommel <carl@codewks.nacjack.gen.nz> posts the weekly news bulletin
|
|
of the ZL Data Group to rec.radio.amateur.digital.misc. This bulletin
|
|
covers the current happenings in New Zeland's packet network.
|
|
|
|
There appears to be a mailing list about NOS on hydra.carleton.ca, but
|
|
I don't have much more detail. Send a message to
|
|
nos-bbs-request@hydra.carleton.ca. The list name is nos-bbs@hydra.carelton.ca.
|
|
|
|
|
|
2.2 What anonymous FTP sites and electronic mail servers are available
|
|
for getting packet radio information and programs?
|
|
|
|
|
|
This is a sampling of FTP sites that carry amateur packet radio related
|
|
files. Consult the Archie archive server for info on locating
|
|
particular files. For more information on using Archie, send mail to
|
|
archie@cs.mcgill.edu with the line 'help'.
|
|
|
|
|
|
ucsd.edu
|
|
|
|
Primary distribution site of KA9Q's derived TCP/IP packages. Also,
|
|
general packet radio information in the /hamradio/packet subdirectory.
|
|
UCSD is also the home of the Amateur Radio "Requests For Comments"
|
|
directory. If you write something that you believe could be included
|
|
in this directory (for example, a specification of AX.25, or maybe some
|
|
other protocol that nobody's thought of before) contact Brian Kantor
|
|
(brian@ucsd.edu) and let him know.
|
|
|
|
wuarchive.wustl.edu
|
|
|
|
Very large collection of amateur radio software. This stuff used to
|
|
be on wsmr-simtel20.army.mil, but that system (and service) was
|
|
discontinued as of 1 Oct 93 for budgetary reasons. WUArchive used
|
|
to "just" mirror Simtel20, and still has all the files that were
|
|
on Simtel20 when it shut down.
|
|
|
|
ftp.cs.buffalo.edu
|
|
|
|
Supplemental archive site for amateur radio information. Contains
|
|
current copies of all rec.radio.amateur.* FAQ's.
|
|
|
|
tomcat.gsfc.nasa.gov
|
|
|
|
Packet software including Baycomm, ROSE, G8BPQ, NOS, etc.
|
|
(I have one report (from George Hitz, W1DA) that this FTP site will be
|
|
down until the end of this summer, 1993. Reportedly the site admin is
|
|
going to be in Sweden.)
|
|
|
|
akutaktak.andrew.cmu.edu
|
|
|
|
SoftKiss for the Mac, in /aw0g. Requires NET/Mac.
|
|
SoftKiss is an init/cdev/driver that allows a MAC to do packet using
|
|
a Poor Man's Packet modem.
|
|
|
|
sumex-aim.stanford.edu
|
|
|
|
NET/Mac is the port of KA9Q's NET program. It doesn't have nifty features
|
|
like scrolling or saving the windows, but the individual sessions can be
|
|
recorded into a file.
|
|
|
|
|
|
As for mail servers, there is only one that I know of at the moment:
|
|
|
|
Ham-Server@GRAFex.Cupertino.CA.US
|
|
|
|
This mail server, which is run by Steve Harding (KA6ETB), has a wide
|
|
variety of information on most aspects of amateur radio, not just digital
|
|
modes. Send a message with the body HELP to get a fairly useful listing.
|
|
Also note that Steve posts the index from the server approximately weekly
|
|
to rec.radio.amateur.misc, rec.radio.amateur.digital.misc, and sbay.hams.
|
|
|
|
|
|
2.3 How do I contact the ARRL via electronic mail?
|
|
|
|
There are various addresses at ARRL HQ, but the most important one is
|
|
probably info@arrl.org. That is where general information about the
|
|
ARRL can be acquired. This address reaches a person, so you'll have
|
|
to specify what/who you're looking for.
|
|
|
|
|
|
2.4 Are there any gateways for mail or news between Internet and
|
|
Amateur Packet radio?
|
|
|
|
Internet / Packet Radio BBS Gateways
|
|
|
|
There are currently two comprehensive gateways between the Internet and
|
|
the packet radio BBS system. One is run by Jim Durham, W2XO, in Pennsylvania
|
|
and the other, which allows access to PBBS bulletins, as well as mail,
|
|
is run by Bob Arasmith, N0ARY, in California.
|
|
|
|
2.4.1 The W2XO Gateway
|
|
|
|
To mail from Internet to Packet:
|
|
|
|
1. Mail to: "bbs@w2xo.pgh.pa.us"
|
|
|
|
2. Make the first line of the text a Packet BBS "send" command, i.e.:
|
|
SP TOCALL @ BBSCALL.ROUTING-HINTS < FROMCALL
|
|
|
|
3. The "subject" line of the Internet mail becomes the "title" line
|
|
of the Packet BBS mail.
|
|
|
|
NOTE: Because of FCC regulations, Jim must hand filter each message
|
|
sent FROM Internet TO the Amateur Packet Radio BBS system. Messages
|
|
should be of minimal length and appropriate content. Read Section 1.9
|
|
(Do's and Don'ts: Rules and Regulations) regarding appropriate usage of
|
|
packet radio for more information. Always include the routing hints
|
|
with the BBS callsign.
|
|
|
|
To mail from Packet to Internet:
|
|
|
|
1. The amateur radio operator must have his callsign registered in
|
|
the gateway alias list. If you want to mail from packet to a specific
|
|
amateur on Internet, send mail to 'durham@w2xo.pgh.pa.us' (Internet) or
|
|
'W2XO @ W2XO.#WPA.PA.USA.NOAM' (Packet BBS mail) with his/her amateur
|
|
callsign and their Internet address.
|
|
|
|
2. Once the above is accomplished, packet BBS mail should be sent to
|
|
'CALL @ W2XO.#WPA.PA.USA.NOAM'. The mail will automatically be
|
|
forwarded to the Internet address of the amateur with the 'CALL'
|
|
callsign.
|
|
|
|
Jim Durham's Internet address is 'durham@w2xo.pgh.pa.us'.
|
|
|
|
|
|
2.4.2 The N0ARY Internet mail <-> full packet BBS gateway
|
|
|
|
Bob Arasmith, N0ARY, runs a gateway between the Internet mail system and
|
|
the PBBS system. His gateway allows you to read, post, and respond to other
|
|
postings on the PBBS system via email. For more information, send mail
|
|
to gateway_info@arasmith.com.
|
|
|
|
|
|
2.4.3 The N6QMY Internet mail <-> full packet BBS gateway
|
|
|
|
Patrick Mulrooney, N6QMY, also runs a gateway between the Internet mail
|
|
system and the PBBS system. His gateway allows you to read, post, and
|
|
respond to other postings on the PBBS system via email. For more
|
|
information, send mail to gateway-info@lbc.com.
|
|
|
|
Users are required to register with the gateway to allow automatic forwarding
|
|
of mail from the Internet to Packet. No registration is needed to send
|
|
mail from Packet to the Internet. To register, send the following
|
|
information to gateway-request@lbc.com:
|
|
CALL:
|
|
FIRST NAME:
|
|
LAST NAME:
|
|
CITY & ST:
|
|
COUNTRY
|
|
ZIP:
|
|
HOME BBS:
|
|
|
|
|
|
2.4.4 LAN Gateways (Packet wormholes via Internet)
|
|
|
|
Currently a group of amateurs are experimenting with connecting packet
|
|
LANs together via Internet IP inside IP Encapsulation. Some of the
|
|
gateways only accept TCP/IP packets, others AX.25 packets. These
|
|
gateways uses the Internet as a transport medium, thus it is impossible
|
|
to access the packet radio network from Internet. For more
|
|
information, join the Gateways mailing list by sending mail to
|
|
"gateways-request@uhm.ampr.org".
|
|
|
|
|
|
2.5 How do I contact TAPR?
|
|
|
|
The only route I currently know if is via USnail and telephone.
|
|
|
|
USnail:
|
|
TAPR (Tuscon Amateur Packet Radio)
|
|
8987-309 E. Tanque Verde Rd. #337
|
|
Tuscon, AZ 85749-9399
|
|
|
|
Telephone:
|
|
Voice: +1 817 383 0000
|
|
Fax: +1 817 566 2544
|
|
|
|
|
|
3 Networking and special packet protocols
|
|
|
|
This is a sample of some of the more popular networking schemes
|
|
available today. By far, there are more customized networking schemes
|
|
used than listed. Consult your local packet network guru for specific
|
|
network information.
|
|
|
|
|
|
3.1 Are there any other protocols in use other than AX.25?
|
|
|
|
AX.25 is considered the defacto standard protocol for amateur radio use
|
|
and is even recognized by many countries as a legal operation mode.
|
|
However, there are other standards. TCP/IP is used in some areas for
|
|
amateur radio. Also, some networking protocols use other packet
|
|
formats than AX.25.
|
|
|
|
Often, special packet radio protocols are encapsulated within AX.25
|
|
packet frames. This is done to insure compliance with regulations
|
|
requiring packet radio transmissions to be in the form of AX.25.
|
|
However, details of AX.25 encapsulation rules vary from country to
|
|
country.
|
|
|
|
|
|
3.2 What is TCP/IP?
|
|
|
|
TCP/IP stands for Transmission Control Protocol/Internet Protocol.
|
|
This is commonly used over the Internet wired computer network. The
|
|
TCP/IP suite contains different transmission facilities such as FTP
|
|
(File Transfer Protocol), SMTP (Simple Mail Transport Protocol), Telnet
|
|
(Remote terminal protocol), and NNTP (Net News Transfer Protocol)
|
|
|
|
TCP/IP doesn't use all of the AX.25 protocol. Instead, it uses
|
|
special AX.25 packets called Unnumbered Information (UI) packets and
|
|
then puts its own special protocol (called IP) on top of AX.25. This
|
|
is used to increase efficiency of its transmissions, since IP does not
|
|
require packets to be "reliable", that is to say, guaranteed delivered
|
|
error-free. TCP handles the retransmission of lost and garbled packets
|
|
in its own way, at a higher level. Therefore the extra information in
|
|
an AX.25 "VC" (virtual circuit) frame is not useful, and thus consuming
|
|
needed bandwidth.
|
|
|
|
The KA9Q NOS program (also called NET) is the most commonly used
|
|
version of TCP/IP in packet radio. NOS originally was written for the
|
|
PC compatible. However, NOS has been ported to many different
|
|
computers such as the Amiga, Macintosh, Unix, and others. Smaller
|
|
computers like the Commodore 64 and the Timex-Sinclair do not currently
|
|
have version of NOS available.
|
|
|
|
For more general information about IP (not necessarily over packet radio),
|
|
try the newsgroup comp.protocols.tcp-ip, and any of the plethora of books
|
|
on the subject. I have found the various books by Douglas Comer (the
|
|
"Internetworking with TCP/IP series) to be excellent.
|
|
|
|
|
|
3.3 How do I get an IP address?
|
|
|
|
Brian Kantor (brian@ucsd.edu) is the IP address coordinator for the AMPR.ORG
|
|
domain, also known as the "44 net." Brian (sensibly enough) delegates
|
|
coordination for each state to sub-coordinators. This list(*) of coordinators
|
|
is available via FTP from ftp.cs.buffalo.edu:/pub/ham-radio/ampr_coordinators.
|
|
|
|
(*) The coordinator list doesn't have e-mail addresses. If you're willing
|
|
to do the legwork required to gather them, please contact Brian Kantor.
|
|
|
|
|
|
3.4 Networking Schemes
|
|
|
|
What are some of those other networking schemes?
|
|
|
|
During the early days of amateur packet radio, it became apparent that
|
|
a packet network was needed. To this end, the following packet network
|
|
schemes where created.
|
|
|
|
|
|
Digipeaters
|
|
|
|
The first networking scheme with packet radio was Digipeaters.
|
|
Digipeaters would simply look at a packet, and if its call was in the
|
|
digipeater field, would resend the packet. Digipeaters allow the
|
|
extension of range of a transmitter by retransmitting any packets
|
|
addressed to the digipeater.
|
|
|
|
This scheme worked well with only a few people on the radio channel.
|
|
However, as packet became more popular, digipeaters soon were clogging
|
|
up the airwaves with traffic being repeated over long distances. Also,
|
|
if a packet got lost by one of the digipeaters, the originator station
|
|
would have to retransmit the packet again, forcing every digipeater to
|
|
transmit again and causing more congestion.
|
|
|
|
|
|
KA-Nodes
|
|
|
|
Kantronics improved on the digipeater slightly and created KA-Nodes. As
|
|
with digipeaters, KA-Nodes simply repeat AX.25 frames. However, a
|
|
KA-Node acknowledges every transmission each link instead of over the
|
|
entire route. Therefore, instead of an end-to-end acknowledgment,
|
|
KA-Nodes allow for more reliable connections with fewer timeouts, because
|
|
acknowledgments are only carried on one link. KA-Nodes therefore are
|
|
more reliable than digipeaters, but are not a true network. It is
|
|
similar like having to wire your own telephone network to make a phone
|
|
call.
|
|
|
|
|
|
NET/ROM
|
|
|
|
NET/ROM was one of the first networking schemes to try to address the
|
|
problems with digipeaters. A user connects to a NET/ROM station as if
|
|
connecting to any other packet station. From there, he can issue
|
|
commands to instruct the station to connect to another user locally or
|
|
connect to another NET/ROM station. This connect, then connect again,
|
|
means that to a user's TNC, you are connected to a local station only
|
|
and its transmissions do not have to be digipeated over the entire
|
|
network and risk loosing packets. This local connection proved to be
|
|
more reliable.
|
|
|
|
NET/ROM is a commercial firmware (software put on a chip) program that
|
|
is used as a replacement ROM in TAPR type TNC's. Other programs are
|
|
available to emulate NET/ROM. Among them are TheNet, G8BPQ node
|
|
switch, MSYS, and some versions of NET.
|
|
|
|
NET/ROM nodes, at regular intervals, transmit to other nodes their
|
|
current list of known nodes. This is good because as new nodes come
|
|
on-line, they are automatically integrated in the network. However, if
|
|
band conditions such as ducting occur, ordinarily unreachable nodes can
|
|
be entered into node lists. This causes the NET/ROM routing software to
|
|
choose routes to distant nodes that are impossible. This problem
|
|
requires users to develop a route to a distant node manually defining
|
|
each hop instead of using the automatic routing feature.
|
|
|
|
|
|
ROSE
|
|
|
|
ROSE is another networking protocol derived from X.25. Each ROSE node
|
|
has a static list of the nodes it can reach. For a user to use a ROSE
|
|
switch, he issues a connect with the destination station and in the
|
|
digipeater field places the call of the local rose switch and the
|
|
distant rose switch the destination station can hear. Other then that,
|
|
the network is completely transparent to the user.
|
|
|
|
ROSE's use of static routing tables ensures that ROSE nodes don't attempt
|
|
to route packets through links that aren't reliably reachable, as NET/ROM
|
|
nodes often do. However, ROSE suffers from the inability to automatically
|
|
update its routing tables as new nodes come online. The operators must
|
|
manually update the routing tables, which is why ROSE networks require
|
|
more maintenance.
|
|
|
|
3.5 BBS message transfer
|
|
|
|
Many of the BBS programs used in packet radio allow for mail and
|
|
bulletins to be transferred over the packet radio network. The BBSes
|
|
use a special forwarding protocol developed originally by Hank Oredsen,
|
|
W0RLI.
|
|
|
|
Besides full service BBSes, many TNC makers have developed Personal BBS
|
|
software to allow full service BBSes to forward mail directly to the
|
|
amateur's TNC. This allows operators to receive packet mail at night
|
|
and avoid tying up the network during busy hours.
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