Telephone Hold Circuits | Electronic Project Circuits

Posts Tagged ‘telephone hold circuits’

Telephone Hold Button

Although a hold feature is standard on most new phones, a lot of us still use the origional bell phones. Those of us that require a hold feature will find this circuit very useful. It is easy to build, and is compact enough to be installed inside the phone with no real problem. It is also powered by the phone line itself, eliminating the need for batteries.

Parts
R1 1 1.5K 1/4 W Resistor
R2 1 1K 1/4W Resistor
D1 1 1N4002 Silicon Diode 1N4003, 1N4004, 1N4005, 1N4006, 1N4007
SCR1 1 C106Y SCR
LED1 1 Red LED Green LED, Yellow LED
S1 1 Normally Open Push-Button Switch
MISC 1 Wire, Board, Case (If Used)

Notes
1. To place a call on hold, simply hold down the button while hanging up the phone. To take a call off hold, just pick up the phone, or any extension.
2. Even though this is a simple circuit, you may have to check with your phone company before use.

Be the first to comment - What do you think? Posted by admin - September 28, 2010 at 4:58 pm

Categories: Basic electronics, Telephone Tags: indicator telephone, telephone control, telephone hold circuits

Phone “Hold” With Music

This circuit will allow you to place a phone call on hold and if you wish to have them listen to music while they are on hold. The circuit operates as follows: The RED wire from the phone jack is typically positive and the GREEN wire is negative or ground. When you want to place a call on hold, close S1 and hang up the handset.
The resistor R1 simulates another phone off hook and allows enough current to pass through to prevent the phone company from disconnecting the call. The resistor R2 and LED provide a visual indication that you have someone on hold ( this is optional ) The capacitor C1 and the transformer provide the interface to a radio or CD player headphone jack. Before you hook up the project to the phone line you must determine the polarity of the line.
Place a voltmeter across the red and green wires of the telephone line, there should be about 48 volts DC positive when the black lead of your meter is connected to the green phone wire. If it is negative 48 volts then reverse the wires.