Abstract: A VSAT communications outdoor unit for satellite communications has a saturated amplifier transmission circuit and a voltage detector. The voltage detector detects insufficient voltage to operate the transmission circuit. A signal generator connects and is responsive to a voltage detector output. The signal generator indicates with an external output that the transmitter is disabled. Preferably, the external output is separate from a link to the indoor unit. A switch for switching between the signal generator and an antenna pointing output responds to the voltage detector output.