This is a small explanation about Interdigit Timeout.
Interdigit timeout is called T302 within CUCM.
To change the interdigit timeout value go to
System => Service Parameters
Select the CUCM server and the “Cisco CallManager” Service.
Once there do search with “CTRL-F” to open up the find window in your browser.
Then search for “302”
This will bring you down to the “T302 Timer” settings field.
Enter the desired value in milliseconds and then click “Save”.
When you are done restart the CCM service.
Navigate to Cisco Unified Serviceabillity
Tools => Control Center – Feature Services
Now select the server then click the radio button for Cisco CallManager and click on “Restart”.
From CUCM in regards to the T302 timer:
T302 Timer :
This parameter specifies an interdigit timer for sending the SETUP ACK message. The timer restarts each time Cisco CallManager receives a digit.
When this timer expires, CUCM routes the dialed digits. For exact timer definitions, refer to the Q.931 specification.
This is a required field.
All Units are in msec.