AT&T MERLIN LEGEND Release 4.0 Feature Reference page 426

Feature Reference
PRI Routing by Dial Plan
Routing by Dial Plan also allows multiple calls to a directory number. Concurrent
incoming calls with the same Called Party Number can be delivered to an
endpoint simultaneously.
The Dialed Number Identification Service (DNIS) is a service attribute of the
Megacom 800 service. Based upon customer-selected parameters, such as
area code, state, or time of call, it provides distinct Called Party Numbers for
incoming 800 and 900 calls. In Releases 1.0 and 1.1, DNIS has the restriction of
one active call per Called Party Number for each B-channel group. The PRI
telephone number, which is matched against the Called Party Number(CdPN),
is used for routing a call to a specific line that normally terminates on a personal
line button. In Release 2.0 and later, the restriction of one active call per CdPN
does not apply.
For each B-channel group, the system can be programmed for either routing by
line appearance or Routing by Dial Plan. With Routing by Dial Plan, the Dial Plan
Routing Table must be programmed to contain a series of patterns—the number
of digits in the Called Party Number (CdPN), network services on which to
match, and a number of digits to add or delete for each match—in order to
route the call to the proper endpoint.
If a B-channel group is programmed for Routing by Dial Plan, all calls into that
B-channel group are routed in a DID-like manner and terminate on an SA
button, a single-line telephone, into a calling group queue, or at a Queued Call
Console (QCC). When an incoming call arrives, its network service type and
Called Party Number are compared to entries in the Dial Plan Routing Table. If
no match is found, the call is routed to the programmed backup position for
unassigned DID calls (normally the primary system operator). If a match is
found, the Called Party Number is manipulated according to the Dial Plan
Routing Table before matching it against the internal Dial Plan to identify an
endpoint to which the call is delivered. If the manipulated Called Party Number
does not match an internal endpoint, it is treated as an unassigned DID call.
If a fast busy tone is programmed as the routing endpoint for unassigned Direct
Inward Dialing calls, the call is rejected. This typically causes the network to
return an intercept tone rather than a fast busy tone. If the number matches an
endpoint that DID calls are not permitted to reach (for example, pool access
codes, group page codes, line access codes, or the ARS access code), the call
is routed to the programmed endpoint for unassigned DID calls (unless the
backup is a fast busy tone).
Table 30 is a sample Dial Plan Routing Table. Note that in the sample table all
incoming calls through the Megacom 800 service are delivered to an endpoint
whose dial plan number is 1234. Entry 15 would be skipped because No
Service is specified.
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Primary Rate Interface (PRI) and T1