NEC DS2000 8 Port Analog Trunk Unit (Refurbished)More Information: The 8ATRU PCB supports 8 analog loop start CO trunks. The PCB has a Mode Switch (for taking the PCB out of service), a status LED indicating proper PCB operation, and a port activity LED that indicates traffic on the PCB. The number of 8ATRU PCBs you can install depends on system configuration. Each 8ATRU PCB also provides 2 power failure cut through circuits. When commercial AC power fails, the PCB automatically cuts through 2 trunk