Call types in a telephone switch | Originating, Terminating, Outgoing, Incoming, Intra-office, Tandem

This page defines Call types in a telephone switch.The types of call are Originating call (O), Terminating call (T), Outgoing call, Incoming call (I), Intra-office call, Tandem call, O+T, O+I etc.

All these terms are associated with telephone switch in teletraffic engineering.

Call types in telephone switch

Let us define call types with respect to figure above. All are related to MSC (Mobile Switching Center).

Originating call

• A call placed by a subscriber of the telephone office.
• Example : Suppose caller-A calls callee-B, then for subscriber A it is called originating call.

Terminating call

• A call received by a subscriber of the office.
• Example : Suppose caller-A calls callee-B, then for subscriber B it is called terminating call.

Outgoing call

• A call going out of the telephone switch or office.

Incoming call

• A call coming into the telephone office from another MSC.

Intra-office call

• A call which originates from and terminates to the same MSC.

Tandem call

• Calls which come in on a trunk from another MSC and go out over a trunk to a different MSC.

O+T call

• The measure of traffic load on the line side of the MSC both from within the switch and from other telephone switches.

O+I call

• The measure of incoming trunk circuit traffic load and traffic load on the MSC.

Useful GSM Links

GSM mobile originated call flow   GSM Mobile Terminated Call flow 
GSM protocol stack   GSM physical layer   GPRS protocol stack   GPRS tutorial  

Other useful Terminologies


RF and Wireless Terminologies