Mike's PBX Cookbook

BARS Flowchart

Basic Automatic Route Selection (BARS) / Network Alternate Route Selection (NARS) is used to prevent users from placing unauthorized toll calls, and to route outgoing calls over the least expensive facility available at the time the call is placed.

There are lots of twists and turns on this journey! The following flowchart shows the process...
Use the cursor keys, or click page corner, to turn pages. Source: Nortel Training Material.


Download the full size images: Page 1, Page 2, Page 3, Page 4.

Process:

A user dials the BARS access code, AC1 (9), followed by a number:

  1. BARS tries to match (a portion of) the dialed digits in the tables
  2. If a match is found, a route is determined for the call
  3. FRL (NCOS) is checked (and optionally TGAR)
  4. Digit manipulation is applied (if necessary)
  5. If a trunk is available, the digit string is sent.

If any of the above steps fail, the caller hears re-order (fast-busy).

The overlays:

LD 86 - FEAT: ESN
  • Define AC1 / AC2 codes
  • Enable CDP for customer
  • Second dial-tone (DLTN)
  • Expensive Route Warning Tone (ERWT)
  • Check TGAR on BARS calls (default: No)

LD 87 - FEAT: NTCL

  • Define NCOS to FRL maps (1 to 1)
  • Define RWTA (expensive tone) for a NCOS
LD 90 - FEAT: NET
  • Type = NPA (Number plan area code transmission)
  • Type = NXX (Central Office Code Translation)
  • Type = SPN (Special Number Translation)

LD 86 - FEAT: RLB

  • Define Route List (RLI) entries (ENTR = entry number)

LD 86 - FEAT: DGT

  • Digit Manipulation tables (added to RLI)

Further information:

More about the SPN Data Block and SPN Alternate Routing.
Information about Cellular Gateway Routing and Alternate Long Distance Carriers.

Refer to the BARS programming course for a more details.
Record RLI's with the Route List Index Worksheet

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