The encoding law used is the μ-law as specified in Recommendation G.711. The sampling rate, load capacity and the code are also specified in that Recommendation.
ITU-T G.746-1993 Referenced Document
ITU-T G.703 Physical/electrical characteristics of hierarchical digital interfaces*， 2016-03-31 Update
ITU-T G.704 Synchronous Frame Structures Used at 154463122048 8448 and 44 736 kbit/s Hierarchical Levels - Series G: Transmission Systems and Media Digital Systems and Networks Digital Transmission Systems - Terminal Equipments - General Study Group 15; 44 pp*， 1998-04-19 Update
ITU-T G.711 PULSE CODE MODULATION (PCM) OF VOICE FREQUENCIES
ITU-T G.712 Transmission performance characteristics of pulse code modulation channels = SERIES G: TRANSMISSION SYSTEMS AND MEDIA DIGITAL SYSTEMS AND NETWORKS - Digital terminal equipments - Coding of analogue signals by pulse code modulation*， 2024-04-19 Update
ITU-T G.713 Performance Characteristics of PCM Channels between 2-Wire Interfaces at Voice Frequencies - General Aspects of Digital Transmission Systems; Terminal Equipments (Study Group XV and XVIII; 12 pp; Replaced by Recmn G.712)
ITU-T G.714 Separate Performance Characteristics for the Encoding and Decoding Sides of PCM Channels Applicable to 4-Wire Voice-Frequency Interfaces - General Aspects of Digital Transmission Systems; Terminal Equipments (Study Groups XV and XVIII) 13 pp
ITU-T G.746 CHARACTERISTICS OF SECOND ORDER PCM MULTIPLEX EQUIPMENT OPERATING AT 6312 kbit/s
ITU-T Q.275 6.5 Data Channel Failure Detection - Specifications of Signalling System No. 6 (Study Group XI) 1 pp
ITU-T G.746-1993 history
1993ITU-T G.746-1993 CHARACTERISTICS OF SECOND ORDER PCM MULTIPLEX EQUIPMENT OPERATING AT 6312 kbit/s