I'd probably review the TCP/UDP port guide and ask them exactly what ports they need, and not how they call them.
http://www.cisco.com/c/en/us/support/unified-communications/unified-communications-manager-callmanager/products-maintenance-guides-list.html
A quick google search came with Plex Media System, so I'm guessing that's just their name for the ports they need.
That PMS from what you say sounds like AXL
HTH
java
if this helps, please rate