4000 Router Series Voice Configuration Guide

When the circuit is idle, the originating side sends a forward seizure signal (00) to the terminating

side, and the terminating side sends back a seizure acknowledgement signal (11). Then the circuit

is seized, and interregister signaling exchange begins. When the called party picks up the phone,

the terminating side sends a backward answer signal (01). After the originating side recognizes

the received signal, it establishes the call.

Figure 16 Call establishment

• Call release at the originating side.

The originating side sends a clear-forward signal 10. When the terminating side recognizes the

clear-forward signal, it sends a backward signal 10. When the originating side recognizes the

backward signal 10, it releases the call.

Figure 17 Call release at originating side

• Call release at the terminating side.

The terminating side sends a clear-back signal 11 to the originating side, and the originating side

sends back a clear-forward signal 10. When the terminating side recognizes the forward signal

10, it sends a release-guard signal 10. When the originating side recognizes the release-guard

signal 10, it releases the call.

Figure 18 Call release at terminating side