Digium, Inc.
Page 42
Chapter 3: Telephone System Configuration
Use the following field definitions as a guide in creating your new analog
trunk definition.
Channels - Select one or more analog channel (port) to be associated
with this trunk.
Trunk Name - Specify a unique name to help you identify this trunk
when it is referred to in other areas such as calling rules.
Busy Detection - This setting is used to detect far end hangup or for
detecting busy signal. Select Yes to enable this feature.
Busy Count - If Busy Detection is enabled it is also possible to spec-
ify how many busy tones to wait for before hanging up. The default is
4, but better results may be achieved by setting to 6 or 8. The higher
the number, the longer it will take to hangup a channel. A higher num-
ber also lowers the possibility of false detections.
Busy Pattern - If Busy Detection is enabled, it is also possible to
specify the cadence of your busy signal. In many countries it is 500
milliseconds on, 500 milliseconds off. Without Busy Pattern specified,
the Asterisk Appliance 50 will accept any regular sound-silence pat-
tern that repeats multiple times as a busy signal. If you specify Busy
Pattern, then the Asterisk Appliance 50 will check the length of the
sound (tone) and silence, which will further reduce the chance of a
false positive.
Ring Timeout - Trunk (FXO) devices must have a timeout to deter-
mine if there was a hangup before the line was answered. This value
can be configured to shorten how long it takes before the Asterisk
Appliance 50 considers a non-ringing line to have hung up.
Answer on Polarity Switch - If this option is enabled the reception of
a polarity reversal will mark when an outgoing call is answered by the
remote party.