unixpc proposed expansion boards

[C M Votava]

As I was snooping through all of my unixpc literature, compiling the unixpc
expansion bus pinouts, I ran across some very interesting items that I
thought would be appropriate to share.

Consider the following excerpt:

=========================================================================
	SYSTEM EXPANSION:

	Three expansion slots are provided, boards inserted into these
	slots will interface to the system via a common expansion bus,
	therefore any expansion board may be plugged into any slot.
	Expansion boards currently under development follow:

	. Memory expansion, 512K bytes when using 64K byte RAM
	  chips, 2M bytes when using 256K byte RAM chips.

	. Voice Storage Module, Voice Storage Services using up to
	  two micro-cassettes. Services include; telephone
	  answering, automatic voice messaging, voice recording.

	. RS-442 Module

	. IBM 327X Coax Interface Module
=========================================================================

Well now, this is very interesting. First, this explains the bus pins
reserved for "Audio From Tape", "Audio From Phone Line" "Audio To Phone
Line", and "Analog Ground". As I can re-construct it, these lines (which
go to the 838A Dial/Network chip (Anybody got a data sheet on this chip?))
were put there so that some expansion board on the bus could send/receive
the analog voice signals through the bus. This was to be that Voice Storage
Module, with the microcassette tapes.

What I'm now interested in is why the Voice Power Board doesn't use these
lines. I'm also going to try and figure out how to make the VP board use
these lines. This way, you could pipe output from the VP board through
the unixpc's on board speaker (I've already written a "soon-to-be-posted
program that will do this via the phone ports). However, I still need to
find data on the 838A chip so I can write programs to use these lines -
PLEASE HELP IF YOU CAN.

Another thing that interests the snot out of me is the RS-442 Module. Does
anybody know anything about this (is Convergent listening??) or at least
give me some hints? I'd love to have an RS-442 interface, just imagine
what you could do -- Faster backups to bigger (and cheaper) cartridge tape
drives, fast communication between units, simple LAN functionality, etc...
Please respond if you can help on this question too.

The IBM interface I'm not too interested in, but maybe others are, if you
know about this one, please send me some information as well.

Thanks...

Craig Votava
[att!]ihlpm!cmv		*** Note changed address ***