To differentiate between multiple modules on the same channel, the remote assigns a unique address to each module during the SYNC process. Think of this as a serial number for each module. Addresses start at A00 and increment up each time a module syncs to the 18R2.
In firmware version 5.1 or lower, COBRA supports 200 addresses (0-199) and 100 channels (0-99). In firmware version 6.0 or higher, COBRA supports 400 addresses (0-399) and 200 channels (0-199).
A device will display the address during the startup sequence while powering on. For the 18M, you can also press and release the TEST button on the module, and the address will display on the three 7-segment displays. The address is displayed persistently after a 36M or 72M finishes booting up; you do not need to press and release the TEST button.
Please note that the 36M skips two addresses and the 72M skips four addresses, but each module only reports the first address on the LCD Display.
The COBRA Audio Box will permanently use channel 99 for its address. You can still use channel 99 for a firing module even if you are using the Audio Box in your show.