Monday, June 1, 2009

Asterisk PBX System Install - 11 Overhead Paging

Issue: Access to Valcom paging system


Overhead paging system
Valcom V-2003A

Our current system requires us to dial *60, at that point you hear a tone, then dial 1 to access the over head speakers and talk into the phone to make the announcement.

Looking at our Cisco routers I see that one of the ports is dedicated to this function.

You can see below that voice port 2/0 is configured as the paging port on the 1760 router.

Cisco 1760 Configuration

voice-port 2/0
trunk-group Outbound 2
input gain 2
output attenuation 2
echo-cancel coverage 32
echo-cancel erl worst-case 0
no vad
no comfort-noise
connection plar 401
impedance complex2
description paging port

To access the port a dial-peer is configured to look for the dial pattern of *60

dial-peer voice 86 pots
destination-pattern *60
port 2/0
forward-digits 0

Now all I need to do is get Asterisk to connected to the Cisco router and pass the dialed numbers (*60) to the router. I read on page 140 of the Asterisk book that Asterisk saves the dialed extension in a variable ${EXTEN}. So let’s edit extensions.conf file.

I added a context called [overhead-paging]

exten => *60,1,Dial(${OUTBOUNDTRUNK}/${EXTEN})
exten => *60,n,Congestion()
exten => *60,n,Hangup()

As you remember OUTBOUNDTRUNK is my variable for the Cisco router (Post 8). So this connects to the router and passes the dialed number of *60.
If there is a problem Congestion gives a fast busy sound, and the line hangs up.

Under the [internal] context I add overhead-paging to the list of included contexts.

include => outbound-local
include => parkedcalls
include => overhead-paging

That’s it. I reload the dialplan and press *60 on one of the phones. This gets passed to the Cisco router. The router matches the *60 to the port for the paging system. I hear the tone, dial 1, and now I can talk over the overhead speakers.

Next problem to work on is Cisco CallManager Intergration

Asterisk PBX System Install - 12 Install H323

Asterisk PBX Install - Index

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