Whats in a Sov coil for this meter to work

[6666]

Whats in the coil for this to work ?

http://dcdetec.com/meter/meter.htm

[Altra]

There is nothing in coil that controls the meter. The fifth wire pin 5, Blue is not connected in the coil. The detector has a DAC which outputs a voltage(pin5) based on the target ID.

Regards

[6666]

Thanks Altra