N0130943 02 Modular ICS 7.1 Installer GuideTrunks and target linesTrunks are external lines that provide the physical connectionbetween a Norstar system and other systems in a private orpublic network. Trunks are numbered 001 to 156 in a fullyexpanded system. Norstar Modular ICS supports six differenttypes of trunks:• PRI trunks are used for incoming and outgoing calls overan ISDN network. PRI SL-1 lines can provide MCDNnetwork functionality in a private network between otherNorstar systems, Meridian 1 systems, or BusinessCommunications Systems, if the appropriate softwarecode has been installed.• T1 trunks are digital trunks that can be configured to act asloop start, ground start, E&M, DID, or leased lines,depending on your requirements.— DID trunks route incoming calls from the publicnetwork directly to telephones within Norstar, withoutan attendant.— Loop start trunks handle incoming and outgoing callsbetween Norstar and the public network.— E&M trunks handle incoming and outgoing trafficbetween the Norstar system and the private network.• BRI trunks handle incoming and outgoing calls betweenNorstar and an ISDN network.• Target lines are virtual communication paths betweentrunks and telephones on the Norstar system. They areincoming lines only, and cannot be selected for outgoingcalls. With 224 target lines in a fully expanded system, youcan concentrate auto answer calls on fewer trunks. Thistype of concentration is an advantage of target lines.Norstar mapping allows you to direct each target line to
