Telephone Watchdog

Telephone Watchdog

Most telephone security devices on the market are simple but quite expensive. These devices provide flashing or buzzing type line eavesdropping/abuse indicators. They typically do not offer guaranteed protection against unauthorized operations. Here is described a very simple and unique telephone watchdog circuit to protect a user's telephone line from any fraud. This small circuit continuously monitors the telephone line and sounds an alarm in any case of abuse. Furthermore, it transmits a loud tone through the telephone line to prevent further abuse.