Cut Phone Line Detector

Electronic Schematics > Telephone related > Cut Phone Line Detector

---

A while ago I got an email asking for the schematic of a circuit to detect cut phone lines. It didn't take me long to find this circuit in Electronics Now. When the circuit detects that a phone line has been cut, it activates a MOSFET which can be used to drive a relay, motor, etc. It can also be connected to a security system.

Schematic

Parts

Notes

1. The "Load" can be a relay, lamp, motor, etc. The circuit can also be connected to a security system to sound an alarm in case the phone line is cut.

2. If the circuit is connected to a security system or other circuit, both circuits must be electrically isolated from each other using an opto-isolator, relay, etc. This also means that the Cut Phone Line Detector must be powered by a seperate 9V supply.

Title: Cut Phone Line Detector
electronic circuit
Source: www.aaroncake.net/circuits/
Published on: 2005-02-10
Reads: 642
Print version:

Other electronic circuits and schematics from Telephone related

---

• Telephone Line Vigilant

• The Link A2B+1 (the Link Telephone Intercom - DTMF version)

• Phone Busy Indicator

• Telephone Audio Interface

• Telephone line monitor

• Simple Phone Tap

• Multipurpose Circuit for telephone

• Off line Telephone tester

• Phone Broadcaster

• The Original 2 Phone Link Design