[comp.dcom.modems] V.32 problems: modems not talking

gandrews@netcom.COM (Greg Andrews) (05/01/91)

In article <665@mixcom.COM> xeee02@mixcom.COM (Dean A. Roth) writes:
>
>The 9600SA and T1600 will not make a V.42 or V.42bis
>connection, but will make a MNP 5 connection.  Both
>will make a V.42bis connection with other modems - just
>not each other.
>

I helped someone troubleshoot a connection where a PM9600SA was calling
a T1600 (ditto for an Intel 9600EX).  We needed to set the PM9600SA
to negotiate V.42/V.42bis ONLY, without allowing fallback to MNP.
Then they were able to link up.  When the T1600 called the PM9600SA,
they liked up with V.42/V.42bis without any special settings needed.

I concluded that something is different about the way the two modems
request V.42, but I couldn't tell exactly what that difference was.

>
>If I use the T1600 to call the USR, or vice versa, I get
>a V.42bis connection.  Eventually, though, one of the modems
>locks (nothing comes or goes).  This behavior has only 
>been observed between these two modems.
>

I use a T1600 to talk with Compuserve's USR DS modems almost every
day.  I haven't noticed any unusual freezeups or disconnections so far...

>Dean Roth           deanr@mixcom.com

-- 
 .------------------------------------------------------------------------.
 |  Greg Andrews   |       UUCP: {apple,amdahl,claris}!netcom!gandrews    |
 |                 |   Internet: gandrews@netcom.COM                      |
 `------------------------------------------------------------------------'

xeee02@mixcom.COM (Dean A. Roth) (05/03/91)

>In article <665@mixcom.COM> xeee02@mixcom.COM (Dean A. Roth) writes:
>>
>>The 9600SA and T1600 will not make a V.42 or V.42bis
>>connection, but will make a MNP 5 connection.  Both
>>will make a V.42bis connection with other modems - just
>>not each other.

A PPI tech support person admited to me (over the
telephone, not in writing) that the 9600SA has problems
talking with a V.32/V.42 Telebit.  Another (the third)
EPROM is in the mail (release 1.31).

The person also said that the older PROMs asserted
carrier detect *before* protocol negotiation was 
completed.  That can explain why I have never been 
able to get a 9600SA to reliably answer calls when
attached to a multi port serial board in a UNIX computer.
It seems to work O.K. when attached to an MS-DOS
computer, though.
-- 
Dean Roth           deanr@mixcom.com