The OC3 IR 4/STM1 SH 1310 card provides four intermediate or short range, ITU-T G.707-, ITU-T G.957- compliant, SDH STM-1 ports. Each port operates at 155.52 Mbps over a single-mode fiber span. The card supports concatenated or non-concatenated payloads at the STM-1 signal level on a per VC-4 basis.