Pass Labs X1 Power Supply Question

Can I use either of the DB-25 receptacles on the back of my X1 power supply? The manual says the "unmarked" receptacle is for future expansion and not used at present. Well, both receptacles are unmarked and I don't want to power up until I know it's hooked up correctly. I have the older smaller black supply.
I would like to thank Larry at High-End Palace for kindly answering my question. Thanks again Larry!