Nortel Modular ICS 7.1, Инструкция по установке

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N0130943 02 Modular ICS 7.1 Installer Guide
Trunks and target lines
Trunks are external lines that provide the physical connection
between a Norstar system and other systems in a private or
public network. Trunks are numbered 001 to 156 in a fully
expanded system. Norstar Modular ICS supports six different
types of trunks:
• PRI trunks are used for incoming and outgoing calls over
an ISDN network. PRI SL-1 lines can provide MCDN
network functionality in a private network between other
Norstar systems, Meridian 1 systems, or Business
Communications Systems, if the appropriate software
code has been installed.
• T1 trunks are digital trunks that can be configured to act as
loop start, ground start, E&M, DID, or leased lines,
depending on your requirements.
— DID trunks route incoming calls from the public
network directly to telephones within Norstar, without
an attendant.
— Loop start trunks handle incoming and outgoing calls
between Norstar and the public network.
— E&M trunks handle incoming and outgoing traffic
between the Norstar system and the private network.
• BRI trunks handle incoming and outgoing calls between
Norstar and an ISDN network.
• Target lines are virtual communication paths between
trunks and telephones on the Norstar system. They are
incoming lines only, and cannot be selected for outgoing
calls. With 224 target lines in a fully expanded system, you
can concentrate auto answer calls on fewer trunks. This
type of concentration is an advantage of target lines.
Norstar mapping allows you to direct each target line to