This Standard provides physical layer performance standards under standard conditions for 12.5 kHz channelization digitally modulated radio equipment with a maximum operating frequency of 1 GHz or less in the Private (Dispatch) Land Mobile Radio Services that employ compatible 4 level frequency modulation (C4FM) or compatible differential offset quadrature phase shift keying (CQPSK) digital modulation for transmission of voice or circuit switched data compliant with the U_m reference point in ANSI/TIA/EIA 102.BAAA, Project 25 Recommended Common Air Interface, which defines the requirements of both the Physical Layer and the Data Link Layer in the OSI reference model.

Telecommunications Systems Bulletin TSB-102, Project 25 System and Standards Definition, provides an overview of Project 25 and lists therein the TIA 102 family of documents developed under that project which was intended to provide interoperable digitally modulated radio equipment for public safety application. Two performance levels have been distinguished herein for certain equipment characteristics. The performance level of Class B is comparable to the performance level for 12.5 kHz analog radio equipment in TIA/EIA-603-1, Land Mobile FM or PM Communications Equipment. Class A describes a higher level of performance for more stringent applications. Should Federal Communications Commission (FCC) requirements as listed in 47 CFR, Code of Federal Regulations, Telecommunication, become more stringent than any standard contained herein, the FCC requirements supersede these.

The standards in this document may be applicable to applications other than those specifically addressed in Project 25. Use of these standards is encouraged for any application of similar equipment; however, the user should review the required standards needed for the specific application.