How to bring a PCM link up between two peers say in between nodeX and nodeY?

Answer 1

Check encoding scheme dblf or crc.
check that trans receive are properly connected.

Answer 2

Once you know SLC (Signalling Line Code) for a particular time slot then these are the few things you can check:

• Trunk b/w source (SSP) and Destination (SCP)
• DPC(Destination Point Code) and OWNSP
• Signaling Link set.
• Network ID(NAT0 & NAT1)
• PCM channel on which link is creating

If these all things are working then your PCM link should be up.