km@emory.uucp (Ken Mandelberg) (05/08/88)
I have a trailblazer+ modem which is causing me a unique
problem. The trailblazer using a signaling scheme with
error correcting protocol that fights right through a
call waiting tone. I only have one phone line and would
much prefer the modem to hangup on the call waiting tone.
Most ordinary modems do in fact hangup when the call
waiting tone interferes with their carrier tone.
What the trailblazer does do when there is "massive"
disruption like the call waiting tone, is go through a
retraining period where it dynamically reselects the
set of signaling frequencies it will use. If I have the
speaker turned on the retraining has a very recognizable
pattern. One piece of this pattern is several seconds of
dead silence, which never is the case when the modem
is not retraining.
If I could build a circuit that would hangup the line
if it detects a second or two of dead silence, it would
solve my problem.
Anyone know an easy way to do this. If there are any
existing phone gadgets that I might coerce into doing this,
all the better.
--
Ken Mandelberg | {decvax,sun!sunatl,gatech}!emory!km UUCP
Emory University | km@emory BITNET
Dept of Math and CS | km@emory.ARPA ARPA,CSNET
Atlanta, GA 30322 | Phone: (404) 727-7963