Vanderbilt RS422 remote transceiver set. The transceiver is placed outside the SPC panel. The maximum cable length (10-core alarm cable) between the SPCW220 and the SPC panel is 200m by default. If the SPCW220 is powered externally, the maximum cable length is 500m (min. 7-wire alarm cable). See also the installation manual for more details. PLEASE NOTE! Compatible with SPC GEN1 with minimum firmware version 3.15 and SPCevo with minimum firmware version 4.1.2.