YA6Q (Yet Another 6386 question): modems

[John Canning]

In article <11305 at cbnews.ATT.COM> mvadh at cbnews.ATT.COM (andrew.d.hay,54242,wi,1d007,508 374 5484) writes:
>In article <2624 at infmx.UUCP> aland at infmx.UUCP (alan denney) writes:
>"Simple question:  what modems (at least 2400 baud) are supported under
>"Sys V/386 3.2.2 on the 6386s (25 and 33 MHz models) for uucp, cu, etc.?
>"There were no AT&T ones listed in the 6386 sales literature.
>
>AT&T makes a 4024 (aka 2224) which includes 2400 baud...
>it has hayes and AT&T command sets...
>

Be careful with modems on the 6386.

For internal modems, we have used the Hayes 2400B and the Okitel
2400B.  With the proper Dialers script, these modems work reliably.
We've seen two odd things with internal modems:  1) when someone
calls in with an IBM 3101 emulator, the system crashes.  2) every
once in a while, the uugetty goes off into space - the modem will
answer, but no login prompt is ever offered; placing an outgoing
call on the modem seems to clear this up.

External modems are a lot less reliable.  With the 2.0 IPC Drivers,
we could always call in, but could only call out once on an external
modem until we reset the system (again, we're talking Hayes and
Hayes compatibles).  With the 3.0 IPC drivers, you can call out as
often as you want.  However, when someone calls in, another process
must access the device before they will receive a login prompt.
We have our users perform an stty.

This work around is a little crazy, but it is the only way we could
get the Hayes compatible modems to work.  The AT&T Hotline blames
this on the Hayes modems and the fact that you must raise RTS (I
think) on the IPC card in order for the modem to raise DTR (I think)
in order for uugetty to be able to open the port and send out the
programming commands.   This is what the \M and \m in the Dialers
script is doing.  Something goes wrong at the end of the programming
command, so that uugetty does not see the rise of DTR (I think)
when a real phone call comes in.

The hotline tells us that AT&T modems (running in the AT&T command
set, NOT the Hayes command set) work reliably with the 3.0 IPC
drivers.  However, we have not had a chance to test these modems
out.

One note about all this - the IPC manual says that the Hayes modem
is supported.  The 3.0 IPC Drivers release note says that the new
software will now handle all supported modems.  The Hotline claims
that only AT&T modems are now supported...

John Canning					...uunet!uvm-gen!banzai!john
The People's Computer Company			...attmail!banzai!john
Williston, Vermont				john at banzai.pcc.com
802-864-0747