Yes both ends must be terminated into a resistance that matches the characterisic impedance of the cable. If you decide to put the 3 resistor bias network on each end feel free to do so. If so then of course the termination impedance is actually a combination of all three resistors. The bias resistors, should you use them have the primary job of putting the comm link to the STOP bit level when the cable is open circuit or all transmitters are shut off.
Michael Karas