Another A/UX question, re: rn, AUX dialup, clarifications

[Alex Nghiem]

In article <947 at ccnysci.UUCP>, alexis at ccnysci.UUCP (Alexis Rosen) writes:
/> In article <7216 at ut-emx.UUCP> nghiem at ut-emx.UUCP (Alex Nghiem) writes:
/> >In article <7139 at dasys1.UUCP>, alexis at dasys1.UUCP (Alexis Rosen) writes:
/> >> Has anyone gotten Hayes-compatible modems working as dial-in devices? My
/> >> (possibly flawed) understanding is that 2400 bps models won't work right.
/> >> I believe this problem is endemic to all SysV based systems. If you have
/> >> a dial-in line working, what modem are you using?
/> >
/> >We have got AUX to work with Microcomm 2400c and 9600+ in AT dumb mode.
/> >Apple is working on problems with running the modems in AT smart mode. AUX
/> >does not work properly with the Everex 2400e, probably the same problem as
/> >above. I understand that AUX dialup will work with Hayes modems.
/> 
/> Please clarify this. Does the Everex fail in the same way as the MicroCom,
> or all the time? Also, could you briefly discuss the "AT dumb mode"? My hayes
/> modem hacking is limited to getting the damn thing running with my terminal
/> emulator...
 
The Everex modem does not answer calls with A/UX, period. 
Initially we thought that the Microcomm modems wouldn't answer
the phone, either. Apple.com got an identical 
Microcomm modem from their lab, tested it, 
and determined that the Microcomm modem would
work in "AT dumb mode". 

The Microcomm modem has two operating modes: a propriety SX mode and
the AT Hayes compatible mode. In the AT Hayes mode, the Microcomm modem can
be set as an intelligent modem where it responds to AT commands (AT smart mode)
or it can be set as a dumb modem where it does not understand AT commands,
but sets up itself according to Hayes-format dipswitch settings (AT dumb
mode). AT dumb mode is okay for a dialup connection, but a problem for 
a dual purpose dialup/dialout connection.

/> How do you 'understand' that the Hayes modems work? Have you used them, or
/> heard reports? If the latter, can you tell us who it is that has the Hayes
/> modems running?

Apple Unix technical support said they had no problems using Hayes(R)
modems with A/UX.

/> >We have found that if carrier is lost for any reason, ie someone
/> >trips over the phone cord, the line is hit by noise, there is a power
/> >failure at the remote end, etc. AUX will not kill the dialup shell process.
/> >Anybody can call back and get into the system. Apple.com is working
/> >on this problem. I have since learned that this may be a SysV problem and
/> >not necessarily just an AUX problem.
/> 
/> If this is true then you are ahead of the game. On some other System V
/> systems, you have to kill the modem BY HAND to get it to work again. There
/> has been much talk about this in various newsgroups (notably pubnet.something)
/> but no definitive conclusion was reached, other than that Hayes-type modems
/> were risky business for SysV machines.

A serial device should be just a serial device to 
A/UX, SysV, Xenix, BSD, or any other Unix, as long as the serial device 
and the serial port conforms to EIA standards. [I assume that you checked
and verified the correctness of the RS-232 cabling] The fact that SysV
and A/UX both seem to have problems with modems 
seems to suggest a relationship [which may or may not exist.] 
A/UX is an implementation of SysV with 4.2BSD extentions
IBM Xenix 2.0 is an implementation, though not complete, of SysV.  
We have had no problems with modems and the 
termination of disconnected dialup shell processes with 
our IBM Xenix system and our University's numerous 4.x BSD systems. 

/> There are other problems. In some cases, if you call in on a 2400 bps modem
/> at 1200, it won't reset the speed. This can cause major problems if your
/> news feed is trying to call at 2400.

We have had no problems with autobaud detect on 
dialup with A/UX or IBM Xenix ver 2.0. With
our Xenix machine, we found that the Everex modem would get stuck at
1200 baud and would not change to 2400 baud afterwards. We determined
that this is a problem with the Everex 2400e because our Microcomm
2400c and 9600+ modems handle baud rate changes correctly. 

Autobaud adjust should be a function of Hayes-
type modems, ie the modem adjusts the
baud rate of the modem's serial output to match the baud rate of the incoming
call. Autobaud detect should be a function of the Unix getty process, ie
getty adjusts the baud rate of the computer's serial port to match
that of the serial device--the modem. Getty on some Unix systems automatically
adjust baud rates upon receipt of an ASCII BREAK. Getty on our Unix systems can
automatically adjust baud rate upon receipt of several carriage returns.
 
/> Note that all this is not rumor. I use a system daily that suffers from the
/> problems I mentioned. It is NOT an A/UX machine, however. If I knew for a
/> fact that A/UX were susceptible or immune wrt these problems, I wouldn't be
/> posting...
/> 
> Does anyone have a non-Hayes-compatible, non-Telebit modem working under A/UX
/> for DIAL-IN use?
/> 
/> Sigh...
/> ----
> Alexis Rosen                       alexis at dasys1.UUCP  or  alexis at ccnysci.UUCP
> Writing from                       {allegra,philabs,cmcl2}!phri\
> The Big Electric Cat                                       uunet!dasys1!alexis
> Public UNIX                           {portal,well,sun}!hoptoad/

I hope I've explained everthing clearly. I also am interested if anybody
has had success with any other modems and A/UX.

nghiem at emx.utexas.edu
"Why?...Because we LIKE you!!!"
_______________________________________________________________________
A Disclaimer for those who need it...

I hereby post this article for factual information only. 
Any misrepresentation, if any, is purely unintentional.
Any opinion expressed or otherwise implicit in these remarks are
solely my own.