SummaryThis Recommendation gives functional characteristics of interfaces associated with: – network nodes, in particular, synchronous digital multiplex equipment and digital exchanges in IDNs for telephony and ISDNs; and – PCM multiplexing equipment. Clause 2 deals with basic frame structures, including details of frame length, frame alignment signals, Cyclic Redundancy Check (CRC) procedures and other basic information. Clauses 3 to 6 contain more specific information about how certain channels at 64 kbit/s and at other bit rates are accommodated within the basic frame structures described in clause 2. |