AT&T AT&T manual ARS Routing Pattern Table, Frl

V1 Systems Only: For calls outside the HNPA (FNPA calls), a check is made against a non-administrable Special Numbers List. The numbers in the list include all “800” and “900” numbers and Telex codes 510, 610, 710, and 810. If a match is found, the call is routed via the local CO facility.

For FNPA calls not on the Special Numbers List (Vi), the dialed numbers are checked against the FNPA Exception List (Vl and V2). Up to 32 entries may be assigned to the list. Each entry must consist of a 3-digit NPA code, 3-digit CO code, and two additional digits (for a total of 8 digits). The last two digits may be “.”, which match any digit. Each entry has an associated ARS Routing Pattern. If a match is found, the call is routed using this pattern. If no match is found, the call is then checked against the NPA Routing Table. A dialed NPA that is listed in the table is routed using the associated Pattern. Numbers that don’t match are routed via the local CO facility.

ARS Routing Pattern Table

Figure 2-9provides a block diagram of an ARS Routing Pattern. Up to eight of these patterns may be administered in the system. Each pattern consists of two subpatterns that may be chosen based on the time of day. Each subpattern (A and B) can contain up to three

allowed		routes. If all routes in a subpattern are busy, a CO		overflow flag (when set) allows
the	call	to be routed via the local CO facility; otherwise, the call			will	queue on the first route
in	the	subpattern.
Administrable Start and Stop times (Hour and Minute) for				Routing		Subpattern		A specify
when Subpattern A should be used			to route calls. Subpattern	B	is used		to route	calls	at	all
other times.
Each route is specified by its trunk			group facility access code	(or	Virtual		Facility code		in	V2)
and	an	associated FRL.

An FRL is typically lower for the first route in a subpattern and increases with each additional route in the pattern. A terminal’s FRL must be equal to or greater than the route FRL for the route to be selected. The system first checks the Route #1 for an available trunk on which to route the call. If the route is busy, Route #2 is checked, then Route #3, if required. If all routes in the subpattern are busy and the CO overflow flag is set, the voice terminal FRL is checked against an associated Overflow FRL before routing the call. For V1 only: If the voice terminal is allowed access to the local CO trunk pool, the system, on overflow, will attempt to place the call regardless of the associated FRLs.

If all routes in a subpattern are busy		and the CO Overflow flag is not set, or	all	CO	trunks
are	busy, the call returns to the first	route in the subpattern and is queued	(if	the	station
FRL	permits access to the first route). The caller is placed in an off-hook queue indicated by
five	short bursts of tone (Preferred Routing Tone). The order of service in the		queue		is First

In First Out (FIFO). An ARS user placed in an off-hook queued state always has precedence over users with a Direct Facility Access buttons. There are 16 slots available in the ARS queue. A route #1 must be specified in the subpattern for a call to queue. If it is not, the caller receives Reorder Tone instead of being queued.

Once a route has been selected, the entries in a Digit Translations Table associated with the selected route’s trunk group (or Virtual Facility in V2) is checked. Based on an associated NPA and the NPA dialed, the system can remove up to 10 digits and then add a pattern of up to 5 digits as specified to route the call.

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