Option 11 PRI needs Listed Number Directory? 1

[HarrisD1200]

Working with a customer with an Option 11 who switched from E&M wink circuits using 4 digit DNIS to a PRI using 4 digit DNIS. Variant is NI-2. Outbound calls worked fine from the PBX, but inbound calls failed every single time to a fast busy. We tried various things (I'm in the CO) to resolve the issue such as changing Variant, different PRI hardware and so on to no avail. Finally, it was suggested that the PRI wasn't working because the Attendant hadn't been given a Listed Directory Number. The PBX vendor did this, and inbound calls started working.

My question is, does this make sense? I want to write it up for future reference, but I'm just not certain that this is what could possibly be causing the problem. Especially since calls directly to extensions not associated with the Attendant failed as well.

Any help would be greatly appreciated, thanks!

 

[cpm23]

Yes. Your LDN tells the PBX how many digits to expect from the CO. If the CO is sending four digits, you can put any unused four digit number in as LDN and incoming calls will work.

 

[HarrisD1200]

CPM23, many thanks for the clarification, and the excellent explanation of how it works.

 

[johnpoole]

and the strange thing, with t1, it works without an ldn with pri's it does not.. it also works with ties without an ldn.. and you can use 4 digit did's and 6 digit ties as long as your switch has the 6 digit tn and you don't program the ties as did's.. (strange beast)

john poole
bellsouth business
columbia,sc