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Using
the sound card in your Asterisk server as a paging output (provides
real-time paging, no “delay).
By John Johnson 8/20/2011
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Following are the instructions for using the soundcard
output in your Asterisk server for paging. I have done this successfully
with several different main board/sound card combination. The output from most sound cards is pretty low
powered, it must be connected to some sort of an amplifier to push overhead
speakers, I have a couple running through Valcom and Bogen overhead systems. This is a handy low-cost
implementation for somebody that already has overhead speakers/amplifier in
place.
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First
make sure the soundcard is enabled in the BIOS and functioning.
Next
edit /etc/asterisk/modules.conf and find the line:
“noload =>
chan_oss.so”
and
change it to
“load => chan_oss.so”
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Then
edit /etc/asterisk/oss.conf and make sure it containg the
following lines (it doesn’t need anything else, so just replace everything
else you find in there with these lines);
[general]
autoanswer=yes
context=from-internal
overridecontext=yes
extension=s
language=en
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Then within the FreePBX
interface add the extension to be dialed to actuate paging as an "Other(Custom)Device" type extension. In the “This device
uses custom technology. dial” field, enter "console/dsp" (without the quotes) and save the new extension.
(This extension can be dialed directly to output to through the soundcard
and to the overhead and it can be included in “paging groups” with other
types of extensions)
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Finally,
from a linux prompt as root perform the following commands to make
sure the modified oss.conf will work;
cd to /etc/asterisk
chmod 0777 oss.conf
{enter}
chown asterisk:asterisk oss.conf
{enter}
Then
restart the system to make sure everything is properly read by asterisk.
You
should now be able to dial the extension you set up for paging and
hear it come out via the soundcard (if, of course, you have some speakers
connected!)
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Upon
system startup, from a linux command line prompt enter: alsamixer
This is the sound mixer control system, you can access
“all” settings by pressing F5. Only some settings are required to be
enabled, (the “mute” function is toggled by moving to the setting and
pressing “m”). This requires some “fiddling around” to get the sound right,
so be prepared to play with it for a while. It seemed easiest to connect a
set of amplified PC speakers and pre-adjust the sound with those before
connecting to the overhead speakers and blasting the whole building right
off the bat. Final adjustments can then be made on the overhead paging
amplifier.
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The
following are some of the references I used to work the above out:
http://www.voip-info.org/wiki/view/Setting+up+paging+with+a+sound+card
https://fonality.com/trixbox/forums/trixbox-forums/help/page-sound-card-and-paging-group
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