[asterisk-users] Sending calls to a particular T1 port.

[Ernie Dunbar]

We have two Asterisk servers. One is a live server supporting our
customers, and the other is a backup server that's being upgraded and
pressed into service. Both servers have a Digium TE405P T1 card in them,
and in order to test the T1 service on the backup server, I've created a
T1 crossover cable (as per
http://www.voip-info.org/wiki/view/crossover+T1+cable) that goes from port
4 on the live server to port 1 on the backup server. Both TE405P's have
been configured, and I get a green light on port 4 on the live server and
port 1 on the backup server.

The problem I have is trying to route calls through this T1 connection. To
the best of my knowledge, this configuration on the live server should
work:

In /etc/asterisk/chan_dahdi.conf:

group=4
context=local
switchtype = national
signalling = pri_cpe
channel => 73-95
context = default
group = 63

In /etc/asterisk/extensions.conf:

exten => _*88,1,Dial(DAHDI/g4/123456789)

However, in the Asterisk console, I get this error on the live server:

    -- Executing [*88 at lightspeedout:1] Dial("SCCP/lightspeed7-00000062",
"DAHDI/g4/123456789") in new stack
[Nov 12 09:24:41] WARNING[1970]: app_dial.c:1286 dial_exec_full: Unable to
create channel of type 'DAHDI' (cause 0 - Unknown)
  == Everyone is busy/congested at this time (1:0/0/1)
  == Auto fallthrough, channel 'SCCP/lightspeed7-00000062' status is
'CHANUNAVAIL'

And no messages at all on the backup server, except this one every 4 seconds:

[Nov 12 10:08:04] WARNING[4473]: chan_dahdi.c:4169 pri_find_dchan: No
D-channels available!  Using Primary channel 24 as D-channel anyway!

Which Googling reveals to be a fairly mundane and harmless warning message
(it happens on real T1's apparently, and isn't related to any kind of
outage).

Also, I'm not entirely sure how to enable changes to chan_dahdi.conf
without restarting asterisk or otherwise killing the 15+ DAHDI channels in
progress. Doing this at off-peak times is very slow, as I'm asleep during
those times, and thus it can only happen once per day.