🚀 go-pugleaf

In article <1992Oct27.160957.2524@abo.fi> MSUORANTA@finabo.abo.fi writes:

>         Does anyone know how one could possibly have
>         more than 4 Com-ports in one computer? I've an 286
>         machine running under Ms-dos 5.0 and as far as I
>         understand the operating system sets the limit.

nope, it's not the operating system, as such.  it's the hardware.
you've got a (very) limited number of interrupt lines (IRQ channels)
to work with, and some of those are reserved for system use.

btw, I'm faced with this exact same problem, and would be very
interested in better answers to this than the one I'm about to
provide....  it works, but it's a work-around, not a true solution.

>         I have to connect:
>         1)      printer (my printer doesn't have parallel)
>         2)      mouse
>         3)      telephone modem *)
>         4)      packet radio modem
>         5)      RTTY-modem

well, first off, you could combine 4 and 5 into an all-mode type
of TNC, such as the Kantronics All Mode (which I use).

I have 2 com ports, COM1 and COM2, plus a SoundBlaster, and parallel
printer port.

COM2 is normally used for a serial mouse (I switched to this from a
bus mouse to get back a com port for when I *NEED* 2 at one time).

COM1 is (normally) used for everything else....  2 TNCs (only one,
the KAM, is normally used) and a high-speed modem.

I also used to have a portable computer from work that might, at any
time, need to access one of these devices, and I setup something
rather simple, but terribly effective, that might help in your case.

I bought a whole bunch of cables (one for each device, and one for each
com port) and setup something like this:

USR DS MODEM <<----------------<    \
KAM (TNC) <<-------------------<     | <----------<< COM1
MFJ 1274 (TNC) <<--------------<    /
MOUSE <<-----------------------<    <-------------<< COM2
                              /\
all taped together ------------
and labelled  ------'

again, COM2 is usually for the mouse, but sometimes it's used for
either of the TNCs.  COM1 is used for whichever of the top 3 devices
I happen to be using at the time.

the idea is based on the patch-panels used in telecom.  overall, it
also ended up being a lot cheaper than the number of switches that
would have been involved to provide the ability for either com port to
access any of the four devices (remember that one of those com ports
used to be on a different computer).  I still have to change cables
around, just like I used to, but now, it's all in one tidy spot.

> Could there be some special device driver which would permit more
> ports in expansion cards?

if anyone is responding to this, please, PLEASE, copy me via e-mail.
our news feed has been flakey lately, but I'd hate to miss the answer
to this one.  :-)
   --jim

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