Hello, I have a question about how to detect does remote endpoint supports H.450 (without using a timer)? Is it clear that receiving endpoint has to replay with a STATUS message in case when it receive an H.450 related FACILITY message? Assume that we have: Originator side sent: -------------------- FACILITY FacilityIE (length=0) ... User-UserIE H323-UserInformation h323-UU-PDU h323-message-body = empty ... h4501SupplementaryService (H.450.x request) ... ... ... Remote side received FACILITY, here is no support for H.450, so we will respond with STATUS message where the causeIE = 100 (invalid IE contents), or 99 (Information element/parameter non-existent or not implemented), or 97 (Message type non-existent or not implemented) STATUS ... CauseIE ... cause = XX diagnostics = YY ... Am I right? Thank you, Alex