This physical line servo control uses components that are not currently common. The circuit is from an 80's documentation and is powered by a voltage according to the servo.
The circuit shown is only for analog telephone lines. I found it in Popular Electronics (1991). It...
We found this amplifier in the Philips Databook of 1990. The stereo circuit has power that reaches 6...
I found this circuit in a Popular Electronics from November 1999. The magazine is no longer...