UC500.com

It looks like Cisco is phasing out the original Cisco Unity Express Network Module and Unity Express Network Module Enhanced Capacity.

The only option to purchase in this form factor now is going to be the Cisco Unity Express Enhanced Network Module NME-CUE and NME-CUE=

It looks like the AIM is still supported.

The Cisco Product announcement is here
http://www.cisco.com/en/US/prod/collateral/voicesw/ps6789/ps5745/ps5520/...