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Automatic Route Selection (ARS) Feature

Description

A table contains some or all of the following types of information:

• Table Type - Indicates how to interpret the information in the table. Table types are: Area Code, Local Exchange, 6-Digit, 1 + 7, Dial 0, Special Numbers (N11), Default Toll, Default Local, and E911 (Release 1.5 and later). Details for each table type are discussed later in this section.
  
  
• Digit Strings � Table includes 3-digit entries, usually area codes or exchanges. Dialed digits are compared to the stored digits. A match should occur in only one table and cause selection of the routes in that table.
  
  
• Subpattern � An array of up to six routes. There are two subpatterns for all tables except the Special Numbers (N11) and Dial 0 tables. The subpattern selected depends on the time of day that the call is made and the start time associated with each subpattern. (The start time for Subpattern A is specified as the stop time for Subpattern B.)

• Routes � A structure that defines possible lines/trunks to be used in a preferred order, usually based on the lowest cost and the extension user�s privilege level or FRL. Routes cannot be programmed for the Special Numbers (N11) Table.

• Pool � A group of lines/trunks that are to be used for this route. A pool must be programmed before any other route information..

• Facility Restriction Level � A value from 0 to 6 associated with the route. For routes, 0 is the least restrictive and 6 the most restrictive value. In order to use a route, a caller (according to extension or Remote Access barrier code/trunk) must have an FRL that is equal to or greater than the FRL of the route.
  
  
• Absorbed Digits � The number (0�11) of user-dialed digits that ARS absorbs (does not dial out) on this route. Digits are absorbed starting with the first user-dialed digit, after any leading star codes.
  
  
• System-Prefixed Digits � A string of up to 20 digits (0�9, *, and Pause) that ARS dials out on this route before dialing any remaining user-dialed digits but after dialing any user-dialed leading star codes.

ARS allows up to 24 programmable tables (16 in Release 1.0), each of which may contain one of the following types of information:

• Area Code Tables. These tables are lists of 3-digit area codes. Area code tables are useful when just one type of line/trunk (for example, a regional WATS trunk) is used for all calls to each area code on the list.
  
  
• Local Exchange Tables. These tables list 3-digit exchanges within the local area code. They can be used to route calls over in-state WATS lines.
  
  
• 6-Digit Tables. If the cost of calls to another area code varies according to the exchange, this table can be used to route calls on different pools, depending on both the area code and the exchange.

• 1 + 7 Tables. In some areas, callers must dial a 1 and a 7-digit number to call certain exchanges, even though the call is within the local area code. A 1 + 7 Table contains a list of local area code exchanges that require dialing a 1 , but not an area code before the 7 digits.

In addition to the fully programmable tables, ARS has five factory-set tables (four in Release 1.0):

• Dial 0 Table. This factory-set table routes calls to numbers that start with 0. The international dialing code, 011, is treated as a special case and can be put into a programmable table. If 011 is not specified in a programmable table, international calls are routed through the Dial 0 Table. Programming of this table is limited to a single pool, its FRL, and system-prefixed digits.
  
  
• Special Numbers (N11) Table. This factory-set table routes calls to the special numbers 411, 611, and 811. The main pool is always used. The pool routing for this table is not programmable.

CAUTION:

Unless networked systems are collocated, each system should have at least one loop-start line connected to the PSTN. The line is required to allow connection of a power-failure telephone to the Power-Failure Transfer (PFT) jack on a module as a power outage backup and for correct routing of emergency and other N11 calls. To ensure that the correct services are reached, if the loop-start line is used for emergency or other N11 calls, it should be assigned to the main pool. In this case, IXC calls determine the number of loop-starts required. See of this guide for more information.

• Default Toll Table. This factory-set table routes toll calls to numbers that do not match entries in any of the area code, 6-digit, or 1 + 7 digits tables. This table has two subpatterns of up to six routes each, but neither absorbed digits nor system-prefixed digits are used.
  
  
• Default Local Table. This factory-set table routes local calls to numbers that do not match entries in the local exchange tables. This table has two subpatterns of up to six routes each, but neither absorbed digits nor system-prefixed digits are used. Routes assigned to the Default Local Table are factory-set with an FRL of 2.
  
  
• E911 Table (Release 1.5 and later). This factory-set table routes 911 emergency calls according to the Enhanced 911 (E911) programming. The tables routes both calls dialed as "911" and calls dialed as "9-911."

The system can have up to 29 tables (20 in Release 1.0), 24 (16 in Release 1.0) of which are fully programmable. The Dial 0, Special Numbers (N11), Default Toll, Default Local, and E911 tables are factory-set and allow limited programming.

Each table (where appropriate) can have two subpatterns (A and B) with an associated start time. The start time for Subpattern A is specified as the stop time for Subpattern B. One subpattern or the other is selected, based on the time of day and the subpattern start time. (If both subpatterns have 00:00 start time, Subpattern A is selected.) Each subpattern can contain up to six routes, listed in order of preference or cost effectiveness.

In addition, each route has an FRL associated with it. The FRL is used to refine the route selection process further. Each extension, Remote Access barrier code, and Remote Access default Class of Restriction (COR) is assigned an FRL from 0 through 6. Each route is also assigned an FRL from 0 through 6. For extensions, 0 is the most restrictive and 6 is the least restrictive level. For lines/trunks, 6 is the most restrictive and 0 is the least restrictive level. An extension can use a route only if its FRL is greater than or equal to the route's FRL. Refer to the Network Reference for information on private network call routing (Hybrid/PBX mode only).

Other digits or special characters may be required so the system can route a call on a particular pool. For example, some companies use an alternate toll call carrier that requires dialing the number with Pause characters and access codes. Each ARS route may have up to 20 characters that are automatically prefixed when a user dials a number. The allowed characters are the digits 0 through 9, *, and Pause. Refer to the Network Reference for information on prepended digits for private network calls (Hybrid/PBX mode only).

ARS also provides an absorb (ignore) digit capability for each route. For example, if the central office does not require a "1" before an area code, the system can be programmed to ignore that first digit. Up to 11 characters can be automatically absorbed when a user dials a number. For 10-digit toll calls, the prefix 1 must be dialed to signal a toll call to ARS. If the central office does not require the prefix 1 for toll calls, the digit absorption feature can be used to eliminate the prefix as the number is dialed. Initially, all 29 tables (20 in Release 1.0) are available for the call.

Topics
	Description
	Tables Programmable Tables Star Codes & Automatic Route Selection Wild Card Characters in 6-Digit Tables ARS Restrictions for VMI Ports How ARS Works Table Selection Route Selection Within the Table Subpatterns Restrictions
	At a Glance
	Enhanced 911 Service
	E911 Partition E911 Adjunct Allow-11
	Considerations & Constraints
	System Programming
	Mode Differences
	Feature Interactions