I am trying to get this connected – and hit a roadblock

The receive +/- 5 volts goes into the back panel J2 connector. I am looking at the schematics but it is not clear to me which pin does what.

The manual says:

                 J2 connector pin #

RxD1                   1                           for the Rx:  which is +5v, -5v, and GND ?

RxD2                   13

RxD3                   17

TxD1                    2                          for the Tx:  which is +5v, -5v, and GND ? 

TxD2                    14

TxD3                    18

Can anyone help ?

Thanks, Fred

VE3WN / VE3PIE