The D125B Powered Loop Interface Module provides two 2-wire loops (A and B) for powered devices. Each 2-wire loop uses a 1.8K ohm end of line resistor for supervision at the end of the loop. The condition of the supervised loop will determine the voltage across the D125B supervisory zone and common as follows:
The D125B supervising zone connects directly to a panel onboard zone with no EOL. The control panel responds to the supervised zone condition using the programmed response for normal, open or short. Connecting an EOL between the D125B supervisory zone and the panel onboard zone will cause a faulted zone regardless of the normal state of the 2-wire loop. Additionally, the supervising zone must connect to a device with a common power connection to the control panel. Polling devices such as Popits or multiplex devices will not work.