The optionally available and retrofittable interface modules IF-KE5 can be installed in the series EA-EL 3000 B and EA-PS 3000 B, adding one or two digital ports or also an analog port. The analog port (sub-d, 15 pole) is coupled with an USB, such as with the combination of USB + LAN. The USB plus analog combination offers the possibility for the user either use digital or analog remote control. The USB, which is included in all three variants, is not only used for digital remote control via SCPI or ModBus command, it also serves for firmware updates.