Branch-generated call identification tones

Last Updated : Oct 30, 2012 |

The branch in a CAS network generates call identification tones, and transmits the tones to the CAS attendant through RLTs. These tones indicate the type of call from the branch, or the status of a call extended to or held at the branch. The attendant hears these tones in the console handset before the attendant is connected to the caller.

The following identification tones might vary by country.

  • Incoming trunk calls: 480 Hz (100 ms), 440 Hz (100 ms), 480 Hz (100 ms) in sequence. The attendant hears this tone immediately after the attendant lifts the handset.

  • Calls from a branch telephone to the main attendant, or calls that are transferred by a branch telephone to the main attendant 440 Hz (100 ms), silence (100 ms), 440 Hz (100 ms) in sequence. The attendant hears this tone immediately after the attendant lifts the handset.

  • Calls that the system extends to an idle telephone, or recall on Does Not Answer: The attendant hears ringback tone (300 ms), and then connection to the normal ringing cycle.

  • Calls that the system extends to a busy telephone, automatically waiting, or recall on Attendant Call Waiting: 440 Hz (100 ms).

  • Calls that the system extends to a busy telephone, waiting denied, or not provided: A busy tone.

  • Remote Hold or Remote Hold recall: A series of four to six cycles of 440 Hz (50 ms), and then silence (50 ms).

  • Recall on Does Not Answer: A burst of ringback tones (300 ms), and then connection to normal ringback at any point in the cycle.

  • Recall from a call that is on Remote Hold: A series of four to six cycles of 440 Hz (50 ms), and then silence (50 ms).

  • Recall from a call that is waiting at a single line telephone: A burst of 440 Hz (100 ms).

The centralized attendant at the main location has access, through RLTs, to all outgoing trunk facilities at the branches in a CAS network. To extend an incoming LDN call to an outgoing trunk at a branch, an attendant can dial the access code and then allow the caller to dial the rest of the number. The attendant can also dial the complete outgoing number.

Calls that are extended to busy single-line telephones at the branch wait automatically. If a call is in queue, the user hears a busy signal. When Station Hunting and Send All Calls is administered, the system routes the call along the administered path. If any extended call is waiting, and is unanswered within an administered interval, the branch system returns the call to the attendant. Call Waiting does not apply to multiappearance telephones. If no appearances are available, busy tone is sent to the attendant, who tells the caller that the line is busy.

The system also routes calls from telephones at the branch to an attendant over RLTs that are seized by the branch system. To reach the attendant, a branch caller dials the attendant-group access code. This access code is administrable. The default is 0. The conversation between the branch caller and the attendant ties up the seized RLT, but calls of this type are usually short.