لینک مدارات تلفن و ارتباطات داخلی

Telephone recording circuit

Telephone In-Use LED Indicator

Telephone In-Use Relay Controller

Telephone audio interface

Infinity Transmitter Schematic and Plans

Digisound ring modulator

Incoming call indicator

Telephone Ring Generator Using 60Hz Power Transformer

Telephone Ring Generator Using Switching Power Supply

Telephone In-Use LED Indicator

Telephone In-Use Relay Circuit

Telephone Audio Interface

Home made PBX / PABX

Ringing Phone Light Flasher

Phone Busy Indicator

FM Telephone Bug

Cut Phone Line Detector

Simple Phone Tap

Telephone Hold Button

Telephone Recorder

Cut phone line detector

Simple phone tap

Telephone auto record

Telephone hold button

Telephone recorder

DTMF tone decoder (Basic Stamp / SSI-202)

DTMF Generator/Decoder

Interface cables for various cell phones

Nokia 3210 MBUS interface

Telephone music on hold box

Telephone ring controlled relay

1-line telephone status indicator (PDF)

Line in use indicator (PDF)

4-line telephone status indicator (PDF)

Caller ID decoder

Telephone in use light

Detecting a telephone RING

Phone In-Use Light

Phone to audio interface

Phone Off-Hook Indicator

'phone rang' indicator light

Phone Line to Audio

Phone in-use

Telephone Line Monitor

Use old phones as an intercom

Phone-In-Use indicator

Hold function for Telephone

Digital/Standard Phone Line Tester

Caller ID decoder part 1

Caller ID decoder part 2

DTMF decoder / logger

FM telephone bug

Universal telephone hold

Talking phone dial monitor

Red box detection circuit (PDF)

Telephone line simulator

Telephone privacy adapter

Telephone ringing circuits

Simple circuit to connect telephone equipment to audio mixer

NCDS Interface Schematic for Nokia 3110, 8110, 8110i

Assorted telephone circuits

Telephone call director (mini PABX)

Phone line sentinel

Telephone ring detector

Telephone line simulator

Cut phone line detector

Telephone ring detector - 4N35

Phone-line privacy circuit

Telephone autodialler

Taxi phone automatic dialler