4-port OC3/STM1 or 1-port OC12/STM4 Channelized Frame-Based Line Module: supports (4) channelized (to DS0) OC3/STM1 or (1) channelized (to DS0) OC12/STM4 frame-based interfaces. Supports the following channelized interfaces: (12) T3, (336) T1, (252) E1; maximum of 2000 channels per line module. Requires channelized OC3/STM1 or OC12/STM4 IOA. Supports 1:1, 2:1, 3:1, 4:1, and 5:1 line module redundancy.