Dear All, We are happy to go with an empty TCS being just the protocol identifier and sequence number AS LONG AS we can send immediately prior to that a cap set delta that removes all existing capabilities WITHOUT waiting for it to be acked. i.e. something like: EP A EP B -- TCS delta to zero --> -- TCS prot and seq only --> ..(transmission delay etc)... <-- TCS Ack for delta --- <-- TCS Ack for prot and seq only -- We want to do this as we feel that the removal of the capabilities should result in the majority of the TCS0 functionality on well behaved H.245 endpoints that don't know about TCS0 (although there is an issue as to whether there are any such terminals!) whereas the other form of TCS will have no effect. If this is acceptable to people, then I will write up some text to say that an empty cap set consists only of protocol identifier and sequence number. Regards, Pete ============================================= Pete Cordell pete@tech-know-ware.com =============================================