Features and functions:
• Monitors "ready to transmit" parallel input signal from antenna switch and generates "transmit inhibit" output signal to the transceiver for maximum operating flexibility and anti-hot switching protection.
• Directly compatible with ACOM 2000A automatic HF linear amplifier and ACOM 2000SW remote antenna switch; control is compatible with other systems via inverse BCD output code and  RS232 serial input for PC etc. 
• Local Network capability, compatible with ACOM 2000A automatic HF linear amplifier.
• Antenna number 7-segment LED indicator plus sound alarm.

Technical specifications:
• Number of antennas selectable : 1 from 10.1 Input control: RS232 +/-12V serial port of ACOM 2000A and/or PC, simple commands.
• Output control: 4-bit inverted parallel BCD code,27V/25mA bit levels.
• Power supply : 120/240VAC internally selectable, +/- 10% tolerance, 50-60Hz, 15VA.
• Operating temperature range : 0 to + 50 C .
• Dimensions: W 131 mm (5-1/8") x H 41 mm (1-2/3") x D 162 mm (6-1/3").
• Weight: 1.3 kg (0.6 lbs).