Special Number Routing
- 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.
1The Special Number Network Translation locates the SPN dialed by the user, and determines a Route List for the call.
|4The route determines a trunk. If LD 86 ESN, TGAR=YES (not default), the users Trunk Group Restriction is checked.|
|2The Route List (RLI) lists possible route entries, each with an FRL, and DMI for this route type, in the order of preference.||5Different routes may require Digit Manipulation (DMI) to modify digits in order to make the digit string compatible.|
|3The facility restriction level (FRL) for a RLI entry restricts access from an NCOS less than this value (see note below).|
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:
|LD 87, PRT, NCTL, 0 9||Print NCOS to FRL relationship (1:1?)|
|LD 90, PRT, NET, SUM, <enter>||Print Network Translation Summary (and find AC1/2)|
|LD 90, PRT, NET, AC1 (AC2), SPN, <enter>||Print Special Numbers for each access code (AC1/2)|
|LD 86, PRT, RLB, <enter>||Print the Route List entries|
|LD 86, PRT, DGT, <enter>||Print the Digit Manipulation tables (if used)|
|LD 21, LTM, <enter>||List Trunk Members (enter for all routes)|