Special Number (SPN) Flow

• A Special Number is a digit sequence that doesn't match the NPA or NXX format.
• An SPN may be any combination of digits, and up to 19 digits in length.
• There is no limit to the number of SPN's programmed in the system.

The steps:

1. The Special Number Network Translation locates the SPN dialed by the user, and determines a Route List for the call.
2. The Route List (RLI) lists possible route entries, each with an FRL, and DMI for this route type, in the order of preference.
3. The facility restriction level (FRL) for a RLI entry restricts access from an NCOS less than this value (see note below).
4. The route determines a trunk. If LD 86 ESN, TGAR=YES (not default), the users Trunk Group Restriction is checked.
5. Different routes may require Digit Manipulation (DMI) to modify digits in order to make the digit string compatible.
6. A trunk is selected, and the (modified) digit string sent. Audio is cut-through, and call setup completed.

Note: An FRL (0-7) is assigned to each NCOS in LD 87 NCTL, and determines which RLI entries it can access. FRL 0 is the most restrictive, 7 is the least restrictive. Therefore, if NCOS and FRL are equal, a higher value NCOS will have fewer restrictions.

What to print?

To build a complete picture of what happens after dialing an access code followed by an SPN, collect the following data:

Commands		Description
LD 87:	PRT, NCTL, 0 9 ↵	Print NCOS to FRL relationship (1:1?)
LD 90:	PRT, NET, SUM ↵	Print Network Translation Summary (and find AC1/2)
LD 90:	PRT, NET, AC1 (AC2), SPN ↵	Print Special Numbers for each access code (AC1/2)
LD 86:	PRT, RLB ↵	Print the Route List entries
LD 86:	PRT, DGT ↵	Print the Digit Manipulation tables (if used)
LD 21:	LTM ↵	List Trunk Members (enter for all routes)

AC1 is for BARS, AC2 is for BARS/NARS: Basic / Network Automatic Route Selection.

• AC1 → BARS = Basic / off switch / commercial call routing, eg: to phone company
• AC2 → BARS/NARS, NARS = Network / private call routing, eg: to campus, inter-site

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