12-Port Channelized/Unchannelized T3 Frame-Based Line Module: supports (12) channelized (DS3, DS1, DS0 with HDLC framing) or (12) unchannelized T3 interfaces. Requires the T312-FO-F3-I/O. Can be used with ERX-12T3-2-1-RMD to support 1:1 and 2:1 line module redundancy.