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SIP Operation Manual
CPT/Cadence Settings
CPT/Cadence parameters serve as the basis of an FXO interface to determine whether or not a
PSTN-call receiving party has hung up the phone. If the following parameters differ from the
parameters of the actual assigned lines, it could cause the FXO to continue to engage a line.
Busy Tone Cadence Measurement
Busy Tone Cadence Measurement: Provide a solution of FXO integrated with PSTN or
PBX. FXO will learn the busy tone automatically.
BTC Detection Sensitivity: The more sensitivity, the more quickly the gateway will cut off
the call. If the gateway often cut off an un-finished call, select less sensitivity.
CPT parameters Table
The CPT has 3 sets of parameter tables. Please adjust the CPT based on local PSTN or PBX.
Moreover, users can use CPT Auto Detect to detect CPT parameters. Instructions are shown in the
following section. The method to detect CPT described as below.
