The dialling process involves the following actions:
After the gateway goes off hook, it may be configured to wait for a dial tone before sending dialling the caller number. This is the behaviour of the gateway when the attribute "Wait For Dial Tone" is set to "YES". Otherwise, the gateway will wait for specified delay (attributes "Pre Dial Delay (ms)") and dial the caller number by sending DTMF digits over the interface.
The attributes "DTMF Digit Duration (ms)" and "Inter Digit Delay (ms)" control the duration of the signal for each digit and the silence period between each digits transmitted over the interface. It is also possible for the gateway to disable the dialling by setting the "Active" attribute to NO. This is usefully only if the equipment behind the gateway wants to perform the dialling operation.