Date: Tue, 04 Jul 2000 07:04:58 +0700
From: "Ronald C.Dailey" <[EMAIL PROTECTED]>
Subject: Re: Timeout Expired
On 2000-07-04 [EMAIL PROTECTED] said:
>"Some computers (particularly 4.77 MHz, 8088 machines) are not
>fast enough to support 19200 or 38400 bps. If you have this
>type of computer, you can use 9600 bps instead, but this will
>not give you the HST's full speed."
>This would imply that with my PC/XT, it wouldn't be possible to
>run faster than 9600 with the USR Courier, even if I got it
>running with it -- which wouldn't be any better than the ZOOM!
That's possible, but if the Courier is a 9600 modem, and not a 14.4
modem, then it should work just as well as the Zoom, and even the Zoom
requires that the port be "locked" at 38400 to operate at its full
potential (using V.42bis data compression). Here are a couple of PCPLUS
2.01 (DOS) Zoom setups which refer to Zoom 9600 models, one of which may
be yours:
Modem "Zoom VP/VX 9600 (no fax)"
initstring="AT&F^M~~~AT&C1&D2&K3 S7=60 S11=60 S95=43^M"
mnp=1
no_connect 3="NO DIALTONE"
no_connect 4="NO ANSWER"
baudrate=38400
Modem "Zoom VFP/VFX 9600 Fax Modem"
initstring="AT&F^M~~~AT&C1&D2&K3 S7=60 S11=60 S95=43^M"
mnp=1
no_connect 3="NO DIALTONE"
no_connect 4="NO ANSWER"
baudrate=38400
Note that the "baudrate" is set to 38400, and in PCPLUS that just means
that you are setting the port to 38400. Obviously, if you don't have a
16550 UART on that port, you can't do that without having some dropped
characters or bytes as you go. The question is whether you want
"authenticity" or a working computer. The fact is that with Net-Tamer,
you can really use the higher speed, but to get it you'll need a serial
port card with a 16550 UART, _or_ you'll need an _internal_ modem rather
than external.
I used internal modems with an old AT&T PC6300 partly because the
built-in motherboard serial port wouldn't handle anything above 9600
very well (it worked okay with an Anchor Volksmodem 12 external 1200 bps
modem for a while). Like your XT, the AT&T had an 8250 UART on that
serial port. There wasn't any way to easily remove the 8250, either, as
it was permanently mounted, rather than socketed. Many people who had
XT computers chose to use internal modems because they save space and a
power outlet, and, as high-speed modems came along, they provide their
own UART (either real or emulated). An internal modem which either has
or emulates a 16550 UART should allow an 4.77 MHz XT to easily support
38400 or even 57600 for the port assigned to that modem.
>However, I've heard of XTs running at 14.4 kbps. Maybe so, but
>I don't want to overwork this old classic, just in case. And I
>wouldn't want to "downgrade" the usefulness of the USR Courier
>for the sake of "authenticity"... ;-)
The key is the serial port. If you have a high-speed external modem
that you want to use on such a system, and you want to use to its full
potential, you really need a high-speed serial port. You just _add_ the
serial card using one of the bus slots that aren't being used. You
follow the directions to set it to a comm port that isn't being used.
If the XT has just COM1, then you can use COM2 and the "standard" IRQ3.
As you should know, if you decide to get a high-speed serial card,
you'll need to get an ISA card (PCI won't work).
Ronald Dailey
--
RCD
Net-Tamer V 1.12.0 - Registered
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