[comp.dcom.modems] Telebit Trailblazer locking in high-speed tones

gedwards@ncratl.Atlanta.NCR.COM (Gordon Edwards) (09/04/90)

I have a Telebit Trailblazer modem that I set to send the PEP high-speed
tones before sending the slower tones for 2400, 1200, and 300 baud.  This
modem talks regularly with another Telebit Trailblazer in PEP mode and with
a few other modems at 2400 and 1200 baud.

Sometimes the modem will answer the phone by sending the PEP tones twice
like it should but when will not switch to the lower speed tones.  The modem
will keep repeating the high speed tones until the modem times out and 
hangs up.  If I call back the same thing will happen over and over.

If I send a ATZ from the system it is connected to and then try the call
again it will cycle through all the tones. 

Question: Why is the modem locking in the high-speed tone sequence???
  How can I keep it from happening?

--
Internet: Gordon.Edwards@Atlanta.NCR.COM                  NCR Corporation
UUCP: uunet!ncrlnk!ncratl!gedwards                        2651 Satellite Blvd.
Amateur Radio: N4VPH                                      Duluth, GA  30136

ralphs@halcyon.wa.com (Ralph Sims) (09/04/90)

gedwards@ncratl.Atlanta.NCR.COM (Gordon Edwards) writes:

> Question: Why is the modem locking in the high-speed tone sequence???

Too many variables to provide an easy solution.

>   How can I keep it from happening?

Try setting S52=2, which will do a hard reset and recall your nvram
settings.  Another suggestion is to send an ATZ each time you re-init
the modem.  I'd try using both.

paul@actrix.co.nz (Paul Gillingwater) (09/05/90)

In article <547@ncratl.Atlanta.NCR.COM> gedwards@ncratl.Atlanta.NCR.COM (Gordon Edwards) writes:
> Sometimes the modem will answer the phone by sending the PEP tones twice
> like it should but when will not switch to the lower speed tones.  The modem
> will keep repeating the high speed tones until the modem times out and 
> hangs up.  If I call back the same thing will happen over and over.
 
I reported this problem to Netcomm, the NZ agent for Telebit, around
about 18 months ago.  It's a known firmware problem, I believe.  The
work around was to change the order of tones, i.e. V22/22bis before
PEP, or vice versa.  Sorry I can't remember which way around they
should go.
-- 
Paul Gillingwater, paul@actrix.co.nz