(ONS 15454 only) The EC1-12 card provides 12 Telcordia-compliant, GR-253 STS-1 electrical ports
per card. Each port operates at 51.840 Mbps over a single 75 ohm 728A or equivalent coaxial span. STS path selection for UNEQ-P, AIS-P, and BER thresholds is done on the SONET ring interfaces (optical cards) in conjunction with the STS cross-connect. The EC1-12 terminates but does not select the 12 working STS-1 signals from the backplane. The EC1-12 maps each of the 12 received EC1-12 signals into 12 STS-1s with visibility into the SONET path overhead.