[comp.sys.tandy] Modem for an HX

ram4152@venus.tamu.edu (MULLINS, ROBERT A) (08/08/90)

I have a 1000hx and a friend has a modem that I can use.  The trouble is
I don't want to pay the outragous price for an upgrade board to add
a serial port.  Does anyone know of any lowcost solutions.  Would it
be possible to use the parallel disk port?  Or is there a way to use
a standard 8-bit card in the Tandy's pin slots, in the way of a converter
I mean.

			Thanks,  Joel  

reyn@trsvax.UUCP (08/09/90)

The "expansion" bus of the hx is "compatible" with the ISA XT bus except
for the conector.  It would be a real kludge, but you could wire a mating
connector to the hx slot to a "standard" card edge connector.  Lord only
knows what kind of noise you might pick up.

An expansion card does exist for using hx cards in a normal PC.  It's
simply a connector wired to the card edge.








					    John Reynolds
Standard disclaimers apply.

jim@rwsys.lonestar.org (James Wyatt KA5VJL .) (08/13/90)

In article <193300223@trsvax> reyn@trsvax.UUCP (Juan Reynolds) writes:
>The "expansion" bus of the hx is "compatible" with the ISA XT bus except
>for the conector.  It would be a real kludge, but you could wire a mating
>connector to the hx slot to a "standard" card edge connector.

The HX's power supply was designed to support only the internals of the HX
and a small amount of expansion. The only hard disk interface I have heard
of used the disk drive's power supply, rather than tax the HX. Most modems
don't draw much power, but other expansion cards (EMS, some network cards,
etc...) thirst for power. Before you try adding something to the HX, check
how much power it uses and, if possible, add an external power supply (+5V)
which shares only ground with the HX. Most network cards need +12V, serial
port cards need -12V and +12V. See the manual or ask the manufacturer.

If you use a ribbon cable with a PC edge socket and a header on it for your
expansion board, keep the cable as short as is practical. As the cable length
grows, the timing skew, induced noise, and neighborhood television problems
get much worse.

The HX is a decent machine to test prototype boards. It sure is better than
risking your 2/3/486 to a 1 a.m. bad solder joint across something important.
At least it has a 3.5 drive and works with a TV. I wonder if it could use one
of the old IBM PC expansion kits... 8{)
----
James Wyatt (KA5VJL) - Standard disclaimer applies...          (H)214-579-0425
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