our company recently moved offices, network settings are EXACTLY the same.

physical connection ...
the isdn and 16xi LAN's connected via crossover,
the WAN's both sit behind a router, both connected to a switch.
we have three isdn lines coming to the 16xi and four isdn lines to the isdn gateway.

on going to the 'status -> sip registration status' of the 16xi i have the following ...
00 77313700 sip.epygi.com Yes 25-Feb-2011 09:50:36

on going to the 'status -> sip registration status' of the isdn i have the following ...
nothing!!!

only three outgoing calls can be made at any one time tho we have seven lines. the extended isdn lines on the quadro isdn are not being used.

how do i test if the two units (quadro 16xi and quadro isdn) are communicating with each other?
how do i test to see if the 16xi is using the lines available on the isdn gateway?
how do i fix it if the units are not communicating?