It is found that Cisco IP phone can receive the Called Party ID and name from Nortel, while Nortel phones cannot receive the Called Party ID and name from Cisco CallManager.
Check these Cisco CallManager service parameters. It is possible that the problem is a mismatch between the Cisco CallManager and Nortel PBX QSIG settings.
In Cisco Call Manager, choose Advanced Button at top of window.
Clusterwide Parameters Device - PRI and MGCP Gateway
ASN.1 ROSE OID Encoding Is it Use Local Value, Use Global Value (ISO) or Use Global Value (ECMA)?
Q.SIG Variant Is it ECMA or ISO?
These two parameters need to match the configuration on the PBXs. These are clusterwide parameters, therefore all PBX trunks must be configured the same as Cisco CallManager.
After the application of these changes, reset the MGCP gateways and check how it works. If the issue still persists, use the TAC Service Request Tool in order to open a case with Cisco Technical Support.