We have a NM-HDV2-2T1/E1 in a 2821 router. We have PRI's from a provider connected to both interfaces. We're seeing a few CRC errors on both interfaces. Currently, we have "no network-clock-participate" with both interfaces set to clock source line. We are planning to set the card to "network-clock-participate" and then "network-clock-select" on the first T1 interface. Then, setting the first T1 interface to clock source line and the second to clock source internal. Is this correct?
Leave default of clock source line for both interfaces. Set network-clock-select with a decreasing priority of your choice.
Note, you don't need the NM-HDV2 in a 2821. You can host the PVDM2 directly on motherboard, and the VWIC in the slots.