AT&T MERLIN LEGEND Release 4.0 Feature Reference page 424

Feature Reference
T308 Timer. Times the delay in network response when the
communications system sends a release message to clear a call.
T309 Timer. Times the duration of a D-channel data link failure (a loss of
signaling for the entire PRI connection).
T310 Timer. Times the network delay following the receipt of a call
proceeding message on an outgoing call.
T313 Timer. Times the delay in network response when the
communications system sends a connect message that indicates the
completion of an incoming call.
T316 Timer. Times the delay in network response when the
communications system sends a restart message to clear a B-channel.
!
CAUTION:
After initial installation, these timers rarely if ever should be changed.
Terminal Equipment Identifier (TEI)
This option assigns the link layer address of a piece of equipment connected to
each D-channel. Normally, only one is connected, and the network assumes
that its TEI is 0.
PRI Call Processing
Figure 35 shows the order of call processing for both incoming and outgoing
calls; the section of the figure within the box applies specifically to call
processing on a system with PRI. An explanation of incoming and outgoing call
processing follows.
Incoming Calls
In Releases 1.0 and 1.1, incoming calls are routed by line appearance.
Beginning with Release 2.0, incoming calls can also apply Routing by Dial Plan,
a routing system for incoming calls administered by the Dial Plan Routing Table
(see Table 30).
Routing by Dial Plan (Hybrid/PBX only)
Routing by Dial Plan is similar in concept to Direct Inward Dialing (DID). It
provides the ability to direct a call automatically to the proper endpoint for
improved call distribution and call handling. Unlike a DID line, a PRI line (or T1
line in Release 4.0 or later) programmed for Routing by Dial Plan can
accommodate outgoing calls as well as incoming calls. As with DID operation,
this feature is available only in Hybrid/PBX mode.
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Primary Rate Interface (PRI) and T1