This standard provides the speciñcation for the MSC-BS interface which coincides with the Reference Point "A" denned in the TR45 Network Reference Model shown in Figure 1-2.

The scope of this standard includes the following topics:

• the MSC-BS interface based on the TIA TR45 Network Reference Model;

• the descriptions of the specined functional capabilities that provide wireless telecommunications services across the MSC-BS interface;

• the descriptions of the division of responsibility of the functions provided between the BS and the MSC without prescribing specific implementations; the descriptions of the MSC-BS Interface standards that support the functional capabilities of the following air interface signaling protocols:

1. ANSI/EIA/TIA -553

2. TIA/EIA IS-54-B

3. TIA/EIA IS-91

4. TIA/EIA IS-95

The BS-MSC interfacecapable of supporting all the seMces offered to mobile subscribers operating under North American Cellular standards.

The MSC to BS interface is specifíed by a set of characteristics, including:

• Physical and electromagnetic parameters.

• Channel structures.

• Message types and contents.

•Network operating procedures.