I had a big issue with a carrier that changed there switch out.My signaling on my 2400 ICS was originally wink start on inbound and immediate on outbound and worked like a champ for 7 years.The carrier said they could not do wink start signaling on there new Metaswitch,so I set my inbound to immediate start which did not work even though they could do immediate start.And the crazy thing about it was that it worked like a champ on immediate start on outbound,but would not immediate start the inbound trunks.I think there is a protocol issue with these new switches that the NEC DTI card does not like...You may have to change to a PRI to make it work...good luck