CCITT Rec. G 704 – SYNCHRONOUS FRAME STRUCTURES USED AT PRIMARY AND SECONDARY HIERARCHICAL LEVELS
1 General
2 Basic frame structures
    2.1 Basic frame structure at 1544 kbit/s
    2.2 Basic frame structure at 6312 kbit/s
    2.3 Basic frame structure at 2048 kbit/s
    2.4 Basic frame structure at 8448 kbit/s
3 Characteristics of frame structure carrying channels at various bit rates in 1544 kbit/s
    3.1 Interface at 1544 kbit/s carrying 64 kbit/s channels
    3.2 Interface at 1544 kbit/s carrying 32 kbit/s channel time slots
    3.3 Interface at 1544 kbit/s carrying n × 64 kbit/s
4 Characteristics of frame structures carrying channels at various bit rates in 6312 kbit/s interfaces
    4.1 Interface at 6312 kbit/s carrying 64 kbit/s channels
    4.2 Interfaces at 6312 kbit/s carrying other channels than 64 kbit/s
5 Characteristics of frame structures carrying channels at various bit rates in 2048 kbit/s interfaces
    5.1 Interface at 2048 kbit/s carrying 64 kbit/s channels
    5.2 Interface at 2048 kbit/s carrying n × 64 kbit/s
6 Characteristics of frame structures carrying channels at various bit rates in 8448 kbit/s interface
    6.1 Interface at 8448 kbit/s carrying 64 kbit/s channels
    6.2 Interface at 8448 kbit/s carrying other channels than 64 kbit/s
ANNEX A – Examples of CRC implementations using shift registers
    A.1 CRC-6 procedure for interface at 1544 kbit/s
    A.2 CRC-5 procedure for interface at 6312 kbit/s
    A.3 CRC-4 procedure for interface at 2048 kbit/s