Older controllers do not have the firmware to recognize the 12 zone modules. A version greater than 1.08 must be installed on the controller for 12 zone module compatibility. To check controller version:
1.) Turn the dial to the Advanced Menu position
2.) Use the up and down buttons to navigate until the screen shows "ABOUT" and then press next.
3.) Use the up and down buttons to navigate until the screen shows "VESRION" and then press next.
The SLM12 is compatible with SL4800 and PL4800 controllers. The SLM12 OBS is compatible with SL1600 and PL1600 controllers.