The OSM-1000-BRD (board only) OSDP-Wiegand Converter is a general purpose Wiegand / OSDP converter. The OSM unit has two operating modes, PD (Peripheral Device) mode and ACU (Access Control Unit) mode. In PD mode, the OSM unit connects a traditional Wiegand reader to an OSDP ACU. In ACU mode, the OSM unit connects an OSDP reader to a traditional Wiegand Access Controller. Additionally, two OSM-1000 units can be used together, one in ACU mode and the other in PD mode, to connect a Wiegand reader to a Wiegand Access Controller with an OSDP connection in between.