The DIN8 connector and connections
This page shows the connections for the DIN8 Jack on the CT-2 board.  The DIN8 jack has input connections for the power and A/D encoders, and output connections for antenna position relays.  All of those functions are documented below.

DIN 8 - Power, Relay, and A/D Connector
1 A/D Input for Elevation
2 CW relay out
3 UP relay out
4 CCW relay out
5 DOWN relay out
6 A/D Input for Azimuth
7 +12 VDC Input to power board
8 Ground

Note: The Up, Down, CW, and CCW outputs are open collector, transistor driven outputs.  They can sink a maximum of 800 milliamps, 100 volts.  We also sell a relay board kit to facilitate controlling your positioning motors.  The relay kit is part number RLY-1.  See the Products page for more information.

Wiring up the A/D Decoders
The A/D decoders are contained within the 16F877 processor chip and can accept a maximum input of +5 volts. So you must wire your potentiometers as shown below to ensure proper operation.

NOTE: Do NOT apply more than +7 volts to the A/D inputs (pin 1 and pin 6) or you will damage the processor. Also, the A/D converter in the processor can only read up to 5 volts.  To ensure protection for the processor, install a 6.2 volt, 1 watt zener diode (1N4735) to ground at each input as shown above at ZD1 and ZD2. (Do not use a 5 volt zener as it will start conducting somewhat below 5 volts and affect the linearity of the readout.)  The 330 ohm resistors are there to protect the zener diodes in case of a high voltage spike on the line.  If you are using our HexFet board or our Relay board to interface to the CT-2 then the zener diodes and resistors are already there and the CT-2 inputs are protected.


Special Note for wiring A/D inputs:  We have discovered that the ground pin (8) of the DIN plug does not supply a resistance-free ground connection.  This will not be problem unless you are using the A/D inputs on the connector.  The problem can be solved by connecting the ground wire(s) in your cable to pin 8 AND to the shell of the connector.  This prevents a lot of display "jitter" when displaying A/D derived values.

Note the grounding in the partially assembled connector shown to the left.

Use with Yaesu G-5500
The DIN8 connector is configured to match the connections to a Yaesu G-5500 rotator control box's External Control jack. If you wire up two DIN8 plugs to match the pinout shown above, you can plug one end to the CT-2 controller and the other end to the G-5500 control box and you are ready to go. In this case the G-5500 supplies +12 volts to the controller board.  Note that the G-5500 rotator supplies the correct voltages to the CT-2 A/D inputs.

Note that the pins are NOT numbered sequentially

Back to Controller