|Definition:|| 1. the assembly, obtained by frequency division multiplexing of a specified number of FDM telephone channels, normally 12, in adjacent positions in a frequency band of specified width, constituting the first level in the standardized frequency division multiplex hierarchy|
2. a frequency band of standardized width, 48 kHz, in a multichannel carrier system and occupying one of a number of specified positions in the spectrum
NOTE 1 – A group is normally an assembly of 12 FDM telephone channels, each of 4 kHz bandwidth. But in some systems, for example those systems used over submarine cables, a group is an assembly of 16 FDM telephone channels, each of 3 kHz bandwidth.
NOTE 1 – Signals, other than those derived from FDM telephone channels, may occupy the whole or a part of the frequency band normally assigned to a group.