"This standard provides the specification for the interfaces which coincide with the Reference Points ""A""@ ""Ater""@ ""Aquater""@ and ""Aquinter"" defined in the TR45 Network Ref8 erence Model shown in [18] and Reference Points 27 and 48 for Legacy MS Support [19]. The scope of this standard includes the following topics: ? MSC-BS and BS-BS interfaces: ? descriptions of the specified functional capabilities that provide wireless telecommunications services across the MSC-BS and BS-BS interfaces as defined in the TR45 Network Reference Model; ? descriptions of the specified functional capabilities that provide wireless tele16 communications services across the MSCe-BS and the MGW-BS interfaces; ? descriptions of the division of responsibility of the functions provided between the BS and the MSC@ and between the source BS and the target BS@ without prescribing specific implementations; ? descriptions of the MSC-BS interface and the BS-BS interface standards that support DS-41 and cdma2000 systems. ? BS-PCF interfaces: ? descriptions of the specified functional capabilities that provide packet data services across the BS-PCF interface; ? descriptions of the division of responsibility of the functions provided between the BS and the PCF without prescribing specific implementations. ? PCF-PDSN interfaces: ? descriptions of the specified functional capabilities that provide packet data services across the PCF-PDSN interface; ? descriptions of the division of responsibility of the functions provided between the PCF and the PDSN without prescribing specific implementations. The interfaces defined in this standard are specified by a set of characteristics@ including: ? physical and electromagnetic parameters; ? channel structures; ? message types and contents; ? network operating procedures; ? user data framing and transport."