The Integrated Services Digital Network (ISDN) User Part defines the protocol which supports the signaling functions required to provide voice and non-voice services in an Integrated Services Digital Network. This standard is based on the Specification of Signaling System No. 7 for international use issued by ITU-T Study Group 11 in the year 2000 and subsequent amendments. This standard is based on and uses, where applicable, the same signaling procedures, parameters, and message types as the internationally specified ISDN User Part of the ITU-T Signaling System No.7. Working group PTSC-IOP has developed this standard to suit anticipated needs and application within and between U.S. networks.