Is the 550 network PRI compatible with DMS250 switch type

[bretv]

DMS250I want to insert the ATLAS 550 between a Network PRI and original phone system utilizing that PRI so I can have a second CPE device share that network resource.  I've done this a number of times, but I've run into a situation where the network PRI switch type appears to be DMS250 (according the original phone system).  I tried using DMS100 switch type and that worked for the user term side PRI for the original phone system, but not for the Network side PRI to the LEC.  I tried both DMS100 and National ISDN with all the different dialing conventions without any success.

I'm checking with the LEC on their specific config and options for changing it, but I could get old(er) and gray(er) waiting on them, not to mention the $$$$ they'll probably request for a few keystrokes.

Any suggestions/experience with DMS250 PRI compatibility options?

[jayh]

ISDN switch types within a family are generally compatible, but the DMS 250 is typically used in tandem configuration and not end-office to a customer. 

As with the Adtran gear, the Nortel can be configured to emulate other switches. It may be configured as AT&T ESS4 which is also typically a tandem-type configuration.

Are you sure that the compatibility issue is related to the switch type?  Specifically what isn't working?