[asterisk-users] app_dial.c: Unable to create channel of type 'Zap' (cause 34 - Circuit/channel congestion)

[Lee, John (Sydney)]

Just to share some experience with everyone about what happened today to
our Asterisk 1.4 box with Digium TE412P card.

We had an unscheduled power outage which shut down the Asterisk box.
When the power went up, Asterisk came back up okay but the ports on the
card were all red.  Zttool show red alarm and cat /proc/zaptel/1 show
red alarm today.

Both incoming and outgoing cannot be made.
When a outgoing call was made, we got the following error message:
app_dial.c: Unable to create channel of type 'Zap' (cause 34 -
Circuit/channel congestion)

We suspect it was the ISDN line problem and so we waited a whole day for
the engineer to arrive.  He plugged an ISDN phone into the line and
found it was working because he could call out.

We are perplexed and thought about replacing the Digium card.  We ended
up just re-seating the card and lo and behold, everything was hunky dory
after re-seating.

Does anyone know why?