(ONS
15454 SDH only) The ONS 15454 SDH MRC-12 card provides up to 12 ITU-compliant multirate ports per card. The MRC-12 card has 12 pluggable port modules (PPMs) with port rates of STM-1, STM-4, and STM-16. In Software R6.0 and later, only 1 PPM port is supported.