P=pressure. T=tank
Tank would be return or drain line. Those units were about 750 psi but I’m not sure the flow rate. I’m guessing 10-15 gpm on typical hydraulic system. They didn’t need a lot of hydraulics to run them.
I am not sure on the connections. In your maintenance manual there should be a hydraulic diagram that should give you some clues of the routing.
Best regards,