An E-1 Line Interface Card. The FAC500 plugin provides four independent E1 Interfaces, supports simplex and duplex COMDAC operation, provides transmit pulse shaping as defined in G.703, Monitors the performance of the received E1 signals (error performance thresholds), sources and monitors alarm indication signal (AIS) and remote alarm indication (RAI), extracts reference timing from received E1 signals, provides E1 loopbacks, supports inventory data, includes built-in self test and fault diagnostics, supports pack protection switching for future releases