Every PBX needs to be able to tell its users when something’s gone awry. CM provides the ability to use announcements for intercepting.

display system-parameters features                              Page   1 of  20
                            FEATURE-RELATED SYSTEM PARAMETERS
[...]
              DID/Tie/ISDN/SIP Intercept Treatment: announcement 3447
[...]

change system-parameters features                               Page   4 of  20
                        FEATURE-RELATED SYSTEM PARAMETERS
 [...]
  Controlled Outward Restriction Intercept Treatment: tone
 Controlled Termination Restriction (Do Not Disturb): tone
           Controlled Station to Station Restriction: tone
 [...]

x


display system-parameters features                              Page  18 of  20
                        FEATURE-RELATED SYSTEM PARAMETERS

INTERCEPT TREATMENT PARAMETERS
       Invalid Number Dialed Intercept Treatment: announcement  3380      
                   Invalid Number Dialed Display:
    Restricted Number Dialed Intercept Treatment: announcement  3381
                   Restricted Number Dialed Display:
   Intercept Treatment On Failed Trunk Transfers? n

The announcements were recorded loosely like this:

3380: “Your call cannot be completed as dialed. Please check the number, and try your call again.”

3381: “The number you have dialed is prohibited from your current class of restriction. If you feel you have reached this recording in error, please contact your telecommunications administrator by calling [(NPA) NXX-XXXX].”

3447: “You have reached [organization name]. The telephone or circuit you have dialed is currently out of service. This condition may be either temporary or permanent; no further information is available at this time. Please hang up, and then try your call again. If you feel you have reached this recording in error, please instead call [(NPA) NXX-XXXX].”

I don’t have announcements set up for the options on page 4 (obviously), mostly because they’re encountered far less (potentially never) than the other three options.