141 lines
6.1 KiB
Modula-2
141 lines
6.1 KiB
Modula-2
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How to get
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S P E E D
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out of your HST and HST Dual Standard Modem
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using
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ACOS Version 2.01d5
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and an Apple IIGS
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-------------------------------------------------------------------------------
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Brought to you by The Oggman, creator of OGG-Net Networking Systems
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Call Infinity's Edge (415) 820-9401 or any OGG-Net BBS
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-------------------------------------------------------------------------------
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HST Basics
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Those of you who have spent big bucks on the HST modem, hoping to get
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14.4K bps, have probably been disappointed, misled, or both. When used with
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ACOS, the HST will only get throughput of 9600 bps with NO COMPRESSION. Why is
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this? Well, its actually pretty simple.
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When you're dealing with high speed modems, you have to differenciate
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between "connect rate" and "DTE rate." Connect rate is the speed in which
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both modems are talking with each other. You can get the connect rate by
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looking at the number after the CONNECT message (ig 1200, 2400, 9600) or by
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looking up the numeric result code. DTE rate is the rate at which the serial
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port is set at when it makes the call.
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HST's can be communicated to with DTE rates of up to 38400 bps. This
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means that, even though its only (!) a 9600 bps modem (so to speak), you can
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actually send commands to it at baud rates of up to 38400. In normal
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operations, the DTE rate will drop down to the connect rate as soon as the
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modem completes a call to the other modem.
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Compression and 14.4K
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---------------------
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In order to use V.42 or MNP Level 5 data compression, THE DTE RATE HAS
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TO BE HIGHER THAN THE CONNECT RATE. Likewise, to get actual throughput of
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higher than 9600 bps (12K, 14.4K), the DTE rate will have to be higher than
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9600. So, for the Apple, this generally means your serial port will HAVE TO
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STAY AT 19,200 BAUD.
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Do you see the problem? ACOS autobauds the serial port to whatever the
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connect rate is. If someone connects at 9600 baud, then the serial port is set
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to 9600 baud, making data compression and high speed totally useless. So, what
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to do about this problem?
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Making the Change
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-----------------
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To make your HST operate at its optimum efficiency, you'll have to fix
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the DTE rate of your modem and make a little change to your ACOS.OBJ file.
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First, run the CONFIG.SYS program and choose GS Modem Port and the HST modem
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(sorry, I haven't deciferd what to do for the SSC yet. Maybe later). Change
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the init string so &D2 is replaced by &B1 (&D2 does absolutely nothing), and
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the X6 is changed to X4. &B1 will fix your modem's DTE rate. Pick 19200 for
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the default baud rate. You should also make sure your NVRAM settings include
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&K1 and &H1. These settings are needed for data compression and flow control.
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Now, load BASIC.SYSTEM and type the following:
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bload acos.obj,a$800 (loads the ACOS.OBJ file)
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call -151 (enter monitor)
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ff0:ea ea ea ea ea ea (make the change)
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bsave acos.obj,a$800,l$5300 (save it)
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Now, all you have to do is run your board and you're set. The modem
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will fix its DTE (the &B1) at 19200 (the default baud rate). When someone
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calls, ACOS will no longer reset the DTE rate to the connect rate, but keep it
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at 19200. Info(2) will still contain the connect rate/300, however.
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Warp Speed on the HST
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---------------------
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So, now we have our HST's zooming along with a fixed DTE rate of 19200.
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This is the best we can get, right? Well, we know that the HST will operate at
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DTE rates of up to 38400 baud, but the Apple IIGS serial port will only go to
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19200. Or will it?
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Well, very recently, Apple guru Guy T. Rice came out with a little CDA
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called Fastport GS 38.4 that will actually open up the Apple IIGS modem port at
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38400 baud. It appears that 19200 is only a firmware limit, not a limit of the
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SCC chip. After decifering Mr. Rice's little desk accessory, I mananged to
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incorporate it into an ACOS mod that will actually fix the DTE rate of the
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modem port to 38400, allowing the maximum throughput of the HST for ACOS 2.0d5
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bulletin boards.
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WARNING: Even with a 7 mhz Transwarp GS card installed, 38400 baud is VERY
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fast and you'll probably get dropped characters. This might not be a problem
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once we get 10 or 13 mhz out of our amazing machines, but until then, do this
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mod with caution. I personally have found no problem with this mod on my 6.25
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mhz GS.
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First, run CONFIG.SYS just as above making the same changes. Run
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BASIC.SYSTEM and type the following:
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bload acos.obj,a$800 (loads the ACOS.OBJ file)
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call -151 (enter monitor)
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ff0:ea ea ea ea ea ea (make the change)
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ffd:20 30 10 ea ea ea ea ea ea ea ea ea ea
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1030:78 a9 0c 8d 38 c0 a9 01 8d 38 c0 a9 0d 8d 38 c0 a9 00 8d 38 c0 60
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bsave acos.obj,a$800,l$5300 (save it)
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Calling Out
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-----------
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As a BBS user, you will also have to do your part in getting the best
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throughput for your HST.
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First, you will also have to fix your modem's DTE rate to the highest
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baud rate possible (19200 normally, 38400 using the Fastport CDA). To do this,
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set your baud rate at its highest level, and type AT&B1&K1&H1 and return while
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in the terminal mode of your term program.
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Now for the hard part. Proterm and most every other term program for
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the Apple has the same problem that ACOS has; it autobauds. I don't have a
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quick fix for this, but you can get around it. Just call the HST board with a
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baud rate of 19200 (or 38400). It will connect at 9600 like normal. Once it
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connects, however, change the baud rate back to what it was. In Proterm, do an
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OA-O and put it back to 19200. If you have the Fastport CDA installed,
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activate it once you connect with the HST board.
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That should do it. If you have any questions, I can be reached at my
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board Infinity's Edge (user #1) or through any board in the OGG-Net network.
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Paul Parkhurst
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The Oggman
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