AT&T DS1/DMi/ISDN-PRI manual DS1 Signal, Framing Format, and ESF Superframe 24 Frames

INTRODUCTION 1-13

end, one framing bit is inserted in each succeeding 193rd bit-position of the DS1 signal. The receive end uses the framing pattern to synchronize the end of one 24-channel block and the beginning of the next, to identify the channels that contain embedded signaling information, and to detect errors.

NOTE: This 4K-bps facility data link is designed to maintain and supervise a DS1 facility. However, this link is used by a System 75 and System 85 DS1s only for transmitting yellow alarms.

Each 24-frame entity, spanning one ESF cycle, is called the ESF superframe. Figure 1-6, DS1 Signal, Framing Format, and ESF Superframe (24 Frames), shows an ESF superframe.

NOTE: For RBS, frames 6, 12, 18, and 24 carry signaling information.

Figure 1-6.DS1 Signal, Framing Format, and ESF Superframe (24 Frames)