932 TN0008589 3.3TT1Digital carrier system or line that carries data at 1.544 Mb/s. These lines can be used toconnect systems on a private network. See also universal T1 Wide Area Network(UTWAN).tandem callingOn a private network, a node can pass a call to one or more nodes on the private network,and then out to the PSTN of the appropriate remote node. This allows a business to reducelong-distance call charges by having the number appear as if it came from the localsystem. Each system must ensure that the appropriate remote access package is assignedto the lines used for the private network, as the system sees calls from outside the system,even if they come over private lines, as remote-access calls, and treats them accordingly.tandem networkThe private networking chapter describes how a tandem network is configured. A tandemnetwork is a group of systems that are linked, each to one or two other systems. Forinstance if you have systems A, B, C, D, E and F, A is connected to B, B is connected to Aand C, C is connected to B and D, and so on. In this case, for a call to move from A to F,which are not connected, the call routes through all the systems between the two.TAPIThe Telephony Application Program Interface (TAPI) is a standard program interface thatlets you and your computer communicate over telephones or video phones to people orphone-connected resources elsewhere in the world.target lineThese are internal system lines used only to answer incoming calls. These lines route callsto specific telephones. A target line routes a call according to digits it receives from anincoming trunk. Program target lines under Target lines (Services, Telephony Services,Lines). Assign target lines to telephones under DN XXX, Line access, Line assignment.(Services, Telephony Services, System DNs). The DID telephony profile automaticallyassigns target lines to all telephone DNs. This profile is picked when your system is firstset up, when you program the Quick Start Wizard. You can configure target lines on morethan one telephone, or multiple times on one telephone. As soon as one call is answered,the line becomes clear and can be picked up by a second telephone or a second line.TATThe Trunk Anti-tromboning (TAT) MCDN call-reroute feature works to find better routesduring a transfer of an active call. This feature acts to prevent unnecessary tandeming andtromboning of trunks.TCP/IPTransmission Control Protocol/Internet Protocol (TCP/IP) is a language controllingcommunication between computers on the Internet.
