the following two methods can be considered. (1) identifying by changing syncword (when transmitter⇔receiver is one-to-one) the setting can be up to 4byte (2^32) of syncword setting. except patterns with extremely large number of 1's or 0's, it is assumed that approximately 2^24 patterns can be used. (2) managing addresses when one transmitter (master) and multiple receivers (slaves) exist, set the addresses of the slaves. the slave units receive only packets destined to themselves (addresses) (using field check function). addresses can be assigned for up to 2^48-1 units (6 bytes).