RS-232 port #2, how to use

I am having problems with my #1 RS-232 port sending programs. I'd like to try port#2, so how do you activate it for communications.

Thanks----Mike

[QUOTEI'd like to try port#2][/QUOTE]

Port #2 is for auxiliary axis communications.
Say a rotary axis driven thru a stand along box.
I don't think you can use it for loading / unloading / DNC to the main control.

Thanks---kinda had that notion. Oh well, it was worth a try.

Mike