ITU-T O.163

Abstract

<strong>General</strong> <br>This specification describes frame alignment signal monitoring equipment for 1544 kbit/s frame structures that are in accordance with Recommendation G.704 [1]. This equipment is intended to monitor 12-frame multiframe (superframe format &#8211; SF) or 24-frame multiframe (extended superframe format &#8211; ESF) structures having either AMI or B8ZS line codes as defined in &#167; 2 of Recommendation G.703 [2]. <br>This equipment shall provide the following capabilities: <br>a) monitor and display the error performance of the frame alignment signal; <br>b) detect and accumulate the counts of occurrences of loss of frame alignment; <br>c) measure and display the error performance of 24-frame multiframe signals by monitoring the cyclic redundancy check (CRC-6) bits and performing a CRC-6 procedure in accordance with Recommendation G.704 [1] and as described below; <br>d) detect and display the various alarm or fault conditions including loss of signal, loss of frame alignment, and other alarm conditions indicated by specific bit patterns. <br>The equipment may optionally provide the following additional capabilities: <br>a) detect and display the code violations in the 1544 kbits signal in accordance with Recommendation O.161; <br>b) provide an external interface for extracting the information bits conveyed in any selected channel time slot; <br>c) provide an external interface for extracting the 4 kbit/s data link bits defined in the 24-frame multiframe structure; <br>d) provide an external interface for extracting the signalling bits in the 12-frame and 24-frame structures.