With the Call Hold (CH) service feature, another telephone call can be displayed or a new connection can be established during an existing telephone connection
. With Call Hold, the subscriber
can hold the existing connection and switch to the new connection. He can then switch back to the original connection. If theuser
switches back and forth between the two connections, he or she is toggling. The hold state is signaled by the hold tone. This signals the voice interruption to the other party while the user can make a consultation call to a second party. Call hold is described in ITU-T Recommendations I.253 and Q.733.2.