TDM means Time Division Multiplex.
Basically any port (anolog, digital, CO, ISDN) that is connected directly via a wire to the PABX.
In avaya lingo you have IP station ports for stations (those talk to a CLAN and a MEDIA PROCESSOR (or MEDIA RESOURCE).
And you have TDM station ports that are connected wita wire to a TNxxxx board
Please let me know if the information that was provided is helpfull.
Edwin Plat
A.K.A. Europe