The field contains the channel map indicating Used and Unused data channels. Every channel is represented with a bit positioned as per the data channel index. The LSB represents data channel index 0 and the bit in position 36 represents data channel index 36. A bit value of 0 indicates that the channel is Unused. A bit value of 1 indicates that the channel is Used. The bits in positions 37, 38 and 39 are reserved for future use.
The ChM value is 5 bytes long. The high 3 bytes are not used.
