Suggested by a Popular Electronics from the 90s, this circuit triggers an external load, relay or recorder, when the telephone line receives a call, thus enabling its recording.
This circuit uses an LM339 and was found in the July 1995 Electronics Now magazine. The LED lights...
We found this circuit in an old Mullard (Philips) documentation on the 555 and 556 integrated circuit...
This circuit was obtained from an 80's documentation from General Electric. The circuit uses an...