Disklavier

Hi! I recently bought a Yamaha G5 grand piano with a separate disklavier control wagon 
ppg10, a machine about 16 years old. I cannot set up the disklavier to transmit what I play on 
the piano keyboard from the MIDI OUT port. The files on the floppy are currently transmitted 
via MIDI OUT. I have no manuals of this machine, so I tried to change the Midi parameters in 
the control wagon, but there is no way to set the MIDI OUT parameter other than DELAYOUT. 
I looked at the cable that connects the piano with the wagon (a multipolar cable with a Mil 
connector at each side) and with a digital tester I noticed that pin 1 at one side of the cable is 
connected to pin 2 at the other side and viceversa; all the other pins instead are connected 
each one to the corresponding number. Can someone help me? Thank you!