Originating register

An originating register (OR) is a circuit in a No. 5 Crossbar telephone switch that provides dial tone for calling subscribers and collects the digits that are dialed into it. Originating registers are used for the dialing portion of the call only, and when dialing is complete, they pass the dialed digits, calling line location, and class of service to a completing marker that takes control of the call, and sets up paths through the switching network to connect the call.

In addition to storing digits, ORs also handle coin collect and return from pay phones, and can be used to return busy signal back to the subscriber in certain instances.

ORs limit the amount of time a subscriber can be connected to them without dialing, and if that time is exceeded, the call is passed to a completing marker, which will connect the call to a permanent signal trunk.

There must be enough Ors in an office to handle the load of concurrently dialing subscribers. Each OR handles one subscriber at a time.