384 lines
18 KiB
Plaintext
384 lines
18 KiB
Plaintext
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Beating Caller ID
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by The Fixer
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v.1.03 98/08/30
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(C) 1998 The Fixer's Tech Room
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For free distribution - you may freely repost & distribute this but not
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for profit without permission of the author. See further restrictions
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at the end of this file.
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To start off with - 12 Ways to beat Caller ID
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(0) This doesn't count as a way to beat CID, but there's a general
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principle to consider when contemplating ways to beat CID.
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Generally, the CID signal your target sees corresponds to the owner
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of the dial tone you call him from. If you call direct, you dial
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from your own dial tone and your line is identified. If you call a
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third party, and by whatever means manage to acquire his dial tone,
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and from there dial out, it is the number associated with that
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second dial tone that your target sees. Some of the ideas following
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this were developed with this basic idea in mind.
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(0.5) This also doesn't count, but remember that beating Caller ID as
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such is only the first layer of your protection. If your calling is
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sufficiently annoying or criminal, there is *always* a paper trail
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(ANI data, billing data, trouble reports, *57 traces, etc) leading
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back to the phone you first called from. That trail is not always
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easy or worthwhile to track you down with. Whether or not the trail
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is followed depends entirely upon how pissed off your target is and
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how much co-operation he can get from the phone company, law
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enforcement, etc.
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(1) Use *67. It will cause the called party's Caller ID unit to
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display "Private" or "Blocked" or "Unavailable" depending on the
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manufacturer. It is probably already available on your line, and if
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it isn't, your local phone company will (most likely - please ask
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them) set it up for free. This is the simplest method, it's 100
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percent legal, and it works.
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(2) Use a pay phone. Not very convenient, costs 25 or 35 cents
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depending, but it cannot be traced back to your house in any way,
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not even by *57. Not even if the person who you call has Mulder and
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Scully hanging over your shoulder trying to get an FBI trace (sic).
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Janet Reno himself couldn't subpoena your identity. It's not your
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phone, not your problem, AND it will get past "block the blocker"
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services. So it's not a totally useless suggestion, even if you
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have already thought of it.
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(3) Go through an operator. This is a more expensive way of doing it
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($1.25-$2.00 per call), you can still be traced, and the person
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you're calling WILL be suspicious when the operator first asks for
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them, if you have already tried other Caller ID suppression methods
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on them.
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(4) Use a prepaid calling card. This costs whatever the per-minute
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charge on the card is, as they don't recognize local calls. A lot
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of private investigators use these. A *57 trace will fail but you
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could still be tracked down with an intensive investigation (read:
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subpoena the card company). The Caller ID will show the outdial
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number of the Card issuer.
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(5) Go through a PBX or WATS extender. Getting a dial tone on a PBX is
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fairly easy to social engineer, but beyond the scope of this file.
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This is a well-known and well-loved way of charging phone calls to
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someone else but it can also be used to hide your identity from a
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Caller ID box, since the PBX's number is what appears. You can even
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appear to be in a different city if the PBX you are using is! This
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isn't very legal at all. But, if you have the talent, use it!
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(6) I don't have proof of this, but I *think* that a teleconference
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(Alliance teleconferencing, etc.) that lets you call out to the
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participants will not send your number in Caller ID. In other
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words, I am pretty sure the dial tone is not your own.
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(7) Speaking of dial tones which aren't yours, if you are lucky enough
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to live in an area with the GTD5 diverter bug, you can use that to
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get someone else's dial tone and from thence their identity.
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(8) Still on the subject of dial tones which aren't your own, you can
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get the same protection as with a payphone, but at greater risk,
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if you use someone else's line - either by just asking to use the
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phone (if they'll co-operate after they hear what you're calling
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about) or by the use of a Beige Box, a hardware diverter or bridge
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such as a Gold Box, or some other technical marvel.
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(9) This won't work with an intelligent human on the other end, it
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leaves you exposed if the called party has a regular Caller ID box
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with memory, and has many other technical problems which make it
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tricky at best and unworkable for all but experts. A second Caller
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ID data stream, transmitted from your line after the audio circuit
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is complete, will overwrite the true data stream sent by the telco
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during the ringing. If the line you are calling is a BBS, a VMB, or
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some other automated system using a serial port Caller ID and
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software, then you can place your call using *67 first, and then
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immediately after the other end picks up, send the fake stream. The
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second stream is what the Caller ID software processes, and you are
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allowed in. See the technical FAQs below for an idea of the
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problems behind this method; many can be solved.
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(10) Someone in alt.2600 (using a stolen AOL account, so I can't credit
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him or her properly) suggested going through 10321 (now 10-10-321)
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or 10288. Apparently using a 10xxx even for a local call causes
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"Out of Area" to show up on the Caller ID display. I live in Canada
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where we don't have 10xxx dialing so I can't verify nor disprove
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this.
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(11) There are 1-900 lines you can call that are designed to circumvent
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Caller ID, ANI, traces, everything. These services are *very*
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expensive, some as high as $5.00 a minute, but they include long
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distance charges. This was first published in 1990 in 2600
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magazine, and in 1993 the IIRG reported that 1-900-STOPPER still
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works. Beware - even if you get a busy signal or no answer, you
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will get charged at 1-900 rates! Another one published in 2600 in
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1990: 1-900-RUN-WELL. That one supposedly allows international
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calls. I'm not about to call either one to find out. Note that you
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could still be caught if the operators of these services were to be
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subpoenaed.
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(12) Use an analog cellular phone. Most providers of plain old analog
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service show up on Caller ID as "Private" or "Out of Area" or a main
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switchboard number for the cell network. This is becoming less and
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less true as cellular providers move to digital cellular and PCS,
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which pass the phone's number on Caller ID. Corollary: Rent a
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cellphone by the day. This might even be cheaper than using a
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prepaid phone card.
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How Caller ID Works
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Caller ID is a data stream sent by the phone company to your line
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between the first and second ring. The data stream conforms to Bell
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202, which is a 1200 baud half-duplex FSK modulation. That is why
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serial Caller ID boxes run at 1200 baud.
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The data stream itself is pretty straightforward. Here's an example:
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UUUUUUUUUUUUUUUUUUUUUUUUUUUUUU<EFBFBD>'^D032415122503806467x
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The first thing of note is the 30 U's. Those are actually sync pulses.
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A "U" is 55 hex, or 01010101 binary. This is called the "Channel
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Siezure Signal."
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After that comes 130 milliseconds of 1200 Hz (the Bell 202 "mark"
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frequency) which usually shows up in the datastream as a character or
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two of garbage.
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That is followed by the "message type word", which is 04 hex for
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standard Caller ID, 07 hex for Name & Number. A word, by the way, is 8
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bits for our purposes.
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That is followed by the "message length word" which tells us how many
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bytes follow.
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The next four bytes are the date, in ASCII. In the example above, the
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date is 0324, or March 24th.
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The next four bytes after the date are the time, also in ASCII. In the
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example, the time is 1512, or 3:12pm.
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The next 10 digits are the phone number that is calling. In the
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example, the phone number is 250-380-6467. The number is also in ASCII
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and doesn't contain the hyphens. Some phone companies will leave out
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the area code and only transmit 7 digits for a local call, others will
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always send the area code as well.
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If this were a name-and-number Caller ID data stream, the number would
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be followed by a delimiter (01h) and another message length byte to
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indicate the number of bytes in the name. This would be followed by the
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name itself, in ASCII.
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If this call originated from an area that doesn't support Caller ID,
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then instead of the phone number, a capital "O" is transmitted (4F hex).
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If the call was marked "private" as a result of the caller using *67 or
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having a permanent call blocking service, then instead of the phone
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number, a capital "P" (50 hex) would be sent.
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The very last byte of the data stream is a checksum. This is calculated
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by adding the value of all the other bytes in the data message (the
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message type, length, number and name data, and any delimiters) and
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taking the two's complement of the low byte of the result (in other
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words, the two's complement of the modulo-256 simple checksum of the CID
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data).
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Some Technical FAQ's
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Q: When I block Caller ID with *67, does it send my number anyway and
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just set a "private bit" so that the other person's Caller ID Display
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unit won't display it?
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A: No. The person you're calling doesn't get your phone number anywhere
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in his data stream if you block your call that way. All he/she gets
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is "P" and the date/time of the call.
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I would like to refer to an experiment I performed in March, 1998
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with a Serial Port Caller ID, which delivers the raw data stream to a
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PC for software interpretation. The following Usenet message (edited
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for this file) is the report I published on that experiment:
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Newsgroups: alt.2600
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From: The Fixer <fixer@bc1.com>
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Date: Tue, 24 Mar 98 16:12:58 -0800
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Subject: Caller ID and *67 - The Facts
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OK, it's time to shovel the bullshit which is piling up in this
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newsgroup about Caller ID.
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A few people are saying that when you block your Caller ID with
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*67, the switch sends your number anyway along with a so-called
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"private bit" that tells the Caller ID display unit to suppress
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display of the number.
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In order to squelch those who'd rather flame back with "show me
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proof" than just read a FAQ, here is the proof. These are
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actual raw data captures from a Bell 202 demodulator (better
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known as a serial port Caller ID) which I captured myself today.
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They prove conclusively that the "Private Bit" is a myth.
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Here is what I got in my raw data stream when I called my voice
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line from one of my BBS lines (which is unlisted, hence the
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PRIVATE string in the name field):
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UUUUUUUUUUUUUUUUUUUUUUUUUUUUUU<55>'^A^H03241512^A2503806467^G^OPRIVATE x
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This is what I got when I did the same thing with *67:
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UUUUUUUUUUUUUUUUUUUUUUUUUUUUUU<55>^P^A^H03241512^D^AO^H^AP(<28>
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The number I was calling from was 250-380-6467. That string is
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clearly displayed in the first (non *67) call. In the number
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field of the second call, only the letter "O" is transmitted.
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In the name field, only the letter "P" is transmitted.
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In both calls, the date and time (03/24, 15:12) is transmitted,
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but transmission of the calling telephone number is suppressed
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in the second call. There is no "private flag" suppressing
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display of the number by the display unit; the calling number is
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not transmitted at all!
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For those of you unfamiliar with the CID raw data stream, the
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U's are actually sync pulses (an ASCII "U" is 01010101 binary).
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The control characters are field delimiters. The first 8-digit
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number is the date and time in MMDDHHSS format. The second
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number in the first call is the phone number, in NPANXXXXXX
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format. That is followed by the name (for those of us with name
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& number CID). The ^O (0Fh) just before the name indicates how
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many characters are in the name - in this case "PRIVATE" is
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padded out with 8 spaces (20h) to make 15 characters. At the
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very end is an 8-bit checksum.
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Believe me, if I were wrong about this, there would be a huge
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marketing frenzy to sell "*67 proof Caller ID boxes" and I would be
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making a fortune selling my Serial Caller ID software, which works
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directly with the data streams illustrated above!
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Q: Can't I just send noise down the line to scramble the Caller ID
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signal between the rings?
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A: No. Your phone line doesn't generate the Caller ID signal. It is
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made by the switch on your calling party's line, and the audio
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circuit between your line and his is not completed until after he
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picks up the phone.
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Q: Do 1-800 numbers have Caller ID? Can I hide my identity from them?
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A: Some do have Caller ID, and the *67 block will work, but many more
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have realtime ANI - Automatic Number Identification. This is an
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older technology which uses a separate line to deliver your number,
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and cannot be blocked. And all 800 subscribers get a list of
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everyone who called them on their monthly bill, blocked or not.
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Q: Can I hide my identity by sending a fake Caller ID signal down the
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line before they answer?
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A: *Generally*, no. The audio circuit between your phone line and their
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line is not completed until the other party picks up. Once they do,
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they would hear your fake signal and know what you were doing...
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unless the person you're calling is very poorly informed or
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untrained. Even so, most Caller ID devices have memory and so the
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person you're calling could just as easily scroll back through the
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box's memory and find your true number.
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Once upon a time, the phone system worked differently, and the audio
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circuit WAS connected even before the called party picked up. A
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device called a "mute" or a "black box" was used to take advantage of
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this fact and allow anyone calling a line with a black box to do so
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toll-free. If the system still worked that way (and there's no
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technical reason why it couldn't in these days of digital switching)
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then yes, it would be very feasible to send a fake Bell 202 data
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stream down the line; in fact you'd hear the real one every time you
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called someone with Caller ID and you'd get a really good feel for
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the timing involved. But if it worked that way, then black boxes
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would also still work, and they don't.
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Q: How about *69? If I protect my call using *67, can they still call
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me back?
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A: Not in 604/250 anyway, and probably not most places.
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Some interesting notes about this: When *69 was first introduced
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here in 250, if you tried to *69 a blocked call, you would get a
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recording telling you that the number could not be announced. And it
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would then offer to connect you anyway! I guess it was business who
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asked for the change because that meant a telemarketer using *67
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would have people call back and their switchboard answer "Sleazebag
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Marketing, how can I help you?". At that point the number was a
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white pages lookup away. So BC Tel, and I would venture to guess its
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parent company GTE and many others, changed it so that *69 won't even
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call back.
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If you find in your area that you CAN call back with *69 to a *67
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protected number, you're a lucky sonofabitch! Why is that? Well,
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with the "old" working of *69, you may still be able to get the
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number of a blocked caller if you are (a) lucky and (b) patient. Take
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your phone off the hook until midnight (if it's a business) or early
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afternoon (if it's a person). THEN activate *69. No incoming calls
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will have come into your line since it was off-hook, so your line's
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*69 last-call register will still have their phone number in it, and
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at those times you are far more likely to get an answering machine
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which may spill the beans as to who called you... clever huh?
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Final Word
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Caller ID can be worked around in so many ways that it really offers no
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value to its subscribers. I am not against the existence of Caller ID,
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as I have been on the receiving end of harassing phone calls and slimy
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telemarketers, all of whom I've been able to put in their place thanks
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to this technology. There's no doubt that Caller ID can help bring
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those who deserve it to justice. But at the same time, we all have the
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right to privacy, and the option to not share your identity with someone
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you're calling is, and always should be, available.
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For this reason, I think that Caller ID should be available free on
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every line as part of the basic service. It's worth nothing anyway!
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---------------------------------------------------------------------------
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That's it. This file may be updated as I receive more information.
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Look for updates on my web site at
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http://ranchonevada.home.ml.org
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or
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http://ranchonevada.ml.org
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or if that doesn't work,
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http://A3A18294.sympatico.bconnected.net
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---------------------------------------------------------------------------
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This file is a freely-distributable copyrighted work. You may repost
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this file free of charge without modifications, but no for-profit
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distribution is allowed without prior arrangement with the author.
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Two individuals who have stolen my work in the past are hereby
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prohibited and enjoined from possessing or distributing this file:
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Pinhead the Cenobite and Jolly Roger. If you are either of these
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individuals, you must delete this file from your system now. If you are
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not, you may not knowingly allow either of these individuals to receive
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this file if it is in your power to prevent such reception. Retention
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||
of this file on your system or on any backup constitutes acceptance of
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||
this term.
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(C) Copyright 1998 The Fixer's Tech Room, a division of Whirlwind
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Software (British Columbia). All rights reserved.
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