Abstract: An oil well installation (15) comprising tubing (17) arranged in a well (18), a pump (19) and actuator (20) disposed in the well, a surface controller (50) connected with the linear actuator, multiple downhole sensors (30-35) configured to sense operating parameters of the linear actuator and/or the pump, a downhole signal processor (40) configured to receive sensor data from the sensors and to output serial data, a communication cable (23) between the sensor processor and the surface controller, the communication cable having at least two paired transmission lines (25, 26), a downhole differential signal driver (41) configured to receive the serial data and to output data signals to the paired transmission lines, and a surface receiver (27) connected to the communication cable and configured to receive the signals from the differential signal driver via the paired transmission lines.