Panasonic KX-TDA100 Prefix for PBX purchased in the U.S.

[selcom]

I have a Panasonic KX-TDA100 Hybrid- IP PBX (purchased in the U.S.A.) and I am trying to install the Panasonic PBX Unified Maintenance Console, but during software installation I am prompted to specify the prefix. I don't see any prefixes on the PBX labels attached to it. Can anyone tell me which prefix I should select for a U.S. PBX?

 

[emycros]

I have the same problem, if you solved yours, I would like to get the same answer.