Page 107 - Asterisk™: The Future of Telephony

Dialplan Configuration
The following minimal dialplan makes use of the Echo() application to verify that bi-
directional communications for the channel are working:
[incoming]
; incoming calls from the FXO port are directed to this context
;from zapata.conf
exten => s,1,Answer()
exten => s,n,Echo()
Whatever you say, the Echo() application will relay back to you.

Dialing In

Now that the FXO channel is configured, let’s test it. Run the zttool application and
connect your PSTN line to the FXO port on your TDM400P. Once you have a phone
line connected to your FXO port, you can watch the card come out of a RED alarm.
Now dial the PSTN number from another external phone (such as a cell phone). As-
terisk will answer the call and execute the Echo() application. If you can hear your voice
being reflected back, you have successfully installed and configured your FXO channel.

Configuring an FXS Channel for an Analog Telephone

The configuration of an FXS channel is similar to that of an FXO channel. Let’s take a
look.

Zaptel Hardware Configuration
The following is a minimal configuration for an FXS channel on a TDM400P. The
configuration is identical to the FXO channel configuration above, with the addition
of fxoks=1.

Recall from our earlier discussion that the opposite type of signaling is used for FXO
and FXS channels, so we will be configuring FXO signaling for our FXS channel. In the
example below we are configuring channel 1 to use FXO signaling, with the kewlstart
signaling protocol:
fxoks=1
fxsks=2
loadzone=us
defaultzone=us
After loading the drivers for your hardware, you can verify their state with the use
of /sbin/ztcfg -vv:

Configuring an FXS Channel for an Analog Telephone | 79