Help with modem

I am on a model 820 running v4r5. We have a 2771 card that I have been told has 
two communication lines possible. One is your "typical" modem cable that we 
attached to an external modem we use for external customer dial in. The other 
is a telephone type of line coming from the same card. I have been told this is 
a 9771. Is anyone familiar with this? From what I can find out this is a line 
that we could connect to a WAN. Does anyone know if I can use this as a 
separate phone line for external customers to dial into, and if so, how, or 
what all can I do with this line?

This is what my hardware communication resources looks like:
 CMB01           284C  Operational           Combined function IOP
   LIN01         2771  Operational           Comm Adapter
     CMN01       2771  Operational           Comm Port
     CMN02       2771  Operational           V.24 Port
 CMB02           2843  Operational           Combined function IOP
   LIN02         2744  Operational           LAN Adapter
     CMN03       2744  Operational           Token-Ring Port
   LIN03         2745  Operational           Comm Adapter
     CMN04       2745  Operational           Comm Port
     CMN05       2745  Operational           Comm Port
 CMB03           2843  Operational           Combined function IOP
   LIN04         2838  Operational           LAN Adapter
     CMN06       2838  Operational           Ethernet Port
   LIN05         2745  Operational           Comm Adapter
     CMN07       2745  Operational           Comm Port
     CMN08       2745  Operational           Comm Port

How do I know which is the 9771? The card position matches up with  LIN01. We 
use CMN02 for the external communications.
Thanks
Dave