Re: PM 2E Framing errors...

John G. Thompson (jgt10@livingston.com)
Wed, 25 Dec 1996 21:41:30 -0800 (PST)

On Wed, 25 Dec 1996, Jay Hennigan wrote:
>
> On Wed, 25 Dec 1996, Andy Thaggard wrote:
>
> > my PM 2E (USR V.34 Sportsers) decided to not let anyone on past port S1
> > yesterday morn. The frame-error were exponentially higher than the rest
> > of the PM. A reboot (and modem juggeling) has made it tolerable...anyone
> > have any experiece with this?

I've helped a few customers with this kind of problem.
Check 1) environmentals - temperature and air circulation, 2) the baud
rate on the ports and 3) the init string.

For sportsters and other light duty modems temperature is a real
problem. They heat up and just go looney tunes.

All of the ports using a type of modem should have the same baud rate and
have it set on all 3 speeds. Sometimes sportsters will work at 115200,
sometimes they won't and you have to drop back to 57600.

An init string I've found works most of the time for sportsters is:

add modem usr-sprt "USR sportster" 57600 \
"at&f1&c1&d2s0=1s2=128s10=20s13.0=1&w0\r^OK"

&f1&c1&d2 - hardware flow control, normal DCD and DTR ops
s13.0=1 - special bit so that the modem resets when dtr drops.
s2=128 disables the escape sequence.
s10=20 - wait 2 seconds with out the carrier on the telco line before
dropping the call.

> > Also, is there any problem with setting the modem speeds to 115* instead
> > of 57600 on the PM? I did not know if the PM would react funny if that
> > was higher than the modems would actually support....
>
> Ummm.... Yes, there's a problem with it. It will give you massive
> framing errors. :-0

It will indeed. It also will result in users not being able to login.

> Framing errors are almost always the result of a mismatch between the
> port speed of the Portmaster and that of the modem.

Yup. They sometimes indicate bad phone lines, but you have to check the
baud rate first.

JGT

--
John G. Thompson       Livingston Enterprises Inc.    Phone: (800) 458-9966
JOAT(MON)              4464 Willow Road                 Fax: (510) 426-8951
support@livingston.com Pleasanton, CA 94588      http://www.livingston.com