The ComNet FDC24NL Series contact closure transceiver units provide transmission of up to twenty four independent duplex dry switch or relay contact closures using a single SFP (Small Form-Factor Pluggable Module, sold separately) optical port or any four-wire RS-422 copper circuit. The FDC24NL Series supports an integrated field expandable RS-422 data bus allowing up to 12 uniquely addressed units to be connected to the bus providing up to 288 unique duplex contact closures over a single SFP optical port or RS-422 copper circuit. The contact closure information is sent in packets that are ordered and encoded, ensuring extremely robust transmission. Packets that are garbled, packets out of sequence, and transmission bit errors will not cause random changes of state on the contact relays. One relay can be optionally re-purposed as a summary fault alarm contact and is triggered in the event that the unit loses fiber or RS-422 bus communications. The FDC24NL series is offered with non-latching solid state relays. Each module incorporates link and individual status indicating LEDs for monitoring confirmation of contact closure input and output of each of the twenty four channels. Packaged in the exclusive ComNet ComFit housing, these units may be either wall or rack-mounted, or may be DIN-rail mounted by the addition of ComNet model DINBKT1 or DINBKT4 adaptor plate.
