The ST-PC4B-SCis a loop powered input/output module with four independent change-over relay outputs and four monitored inputs. The outputs feature N/O and N/C volt free contacts and can be driven separately under the control of the fire alarm panel, to be used for the control of devices such as dampers or for plant and equipment shutdown. The four inputs are provided for local fire and fault monitoring and these are fully monitored for open and short circuit, which if required, can be enabled or disabled in pairs using a two-way DIL switch. Note:- The state of the relay contacts will be indeterminate until the unit is powered. The unit is also available in a DIN Rail mountable enclosure (ST-PC4D-SC ). A back box is also available (ST-MBB) which, when used in conjunction with the ST-PC4B-SC, increases the IP rating to IP65.