🚀 go-pugleaf

In article <1992Oct12.150522.1@alien.gici.com>, laut@alien.gici.com (Bill Laut) writes:
> 
> 	We're thinking of replacing some modems with v.42bis in order to
> achieve the (theoretical) 115.2kb in asynch mode.  The only problem we're
> facing is that we cannot do a "$ SET TERM/SPEED=115200" (:-).

You're not likely to get anywhere near 115.2 KB on anything but highly
redundant data.  I don't know what your application is, but for typical
data you won't get much benefit beyond 38.4 KB, and if it is already
compressed (by lzcmp or ZIP for example), then you won't get beyond
maybe 19.2 KB if that, depending on whether the modem's compression
algorithm can do any better than the one being dome by the CPU.

> 	Therefore, does anyone know of an intelligent Q-22 card that can
> plug into a MicroVAX-II, and which has the following properties:
> 
> 	1)  Has a self-contained CPU which we can program
> 	2)  Has a full-modem asynch UART that can hit 115.2k
> 	3)  Preferably does DMA into the MicroVAX-II

The KXT11 and KXJ11 cards from DEC can do all but the second; I forget
what their maximum baud rate is but I think it's 38.4.  Unfortunately I
no longer have any of the manuals for them around to check.  They have
a PDP-11 chip on them so if you're familiar with that architecture they
are pretty easy to program.  You can download code to them or burn ROMs
to put on the card.  They also have a very flexible DMA capability,
although programming it is a little odd compared to most other DEC
devices.  You can either program them in MACRO-11 if you have, say, an
old RT11 system lying around to do the programming;  or you can get the
VAX RSX product and program them with that.

They're fairly expensive if you get them new from DEC, but I've sometimes
seen them for sale used for dirt cheap prices so if you're interested in
them you should probably shop around.

Good luck,

Bruce C. Wright