The Model LIM-1 Loop Isolator module from Siemens Industry, Inc., isolates short circuits on MXL and FireFinder-XLS intelligent device loops. By placing devices between LIM-1s during installation, a short in the wiring within that group is disconnected from the rest of the loop. The remainder of the devices continue to operate. The LIM-1 operates in both Class A and Class B circuits.

A yellow LED flashes when a device detects a short circuit. The LIM-1 then isolates that part of the loop. When the short is removed, the LIM-1 automatically restores the loop to normal operation. The LIM-1 does not have a loop address and therefore does not require address programming nor does it reduce the loop capacity below 60 (MXL) or 252 (XLS) devices.