Phone circuits are busy pointer. A busy signal is a signal that indicates that someone is trying to call a phone number but could not be contacted because the phone if it is not involved, or because the circuits are busy, calls are impossible to solve.
On many phones, busy signals take the form of a distinctive tone, but a busy signal can also be visual, as in the case yanga phone designed for users of deafness or hearing impairment. Many people are familiar with a busy signal sounds, because significantly different from the dial tone, a tone that indicates that the phone line is open and ready to be called.
In most cases, only a busy signal indicates that the person you are calling is a call. A busy signal will also sound when the phone is turned off. In this case, the signal indicates that there are no technical obstacles to placing the call, but calls can not be completed because the phone is in use.
In some cases, you can ask the operator to enter, if you call in an emergency, in this case the operator will interrupt the call and inquire whether the subject is willing to take your call.
Have you ever use a modem or fax and someone else pick up the phone, disconnect? Phone circuits are busy these simple pointers that will end all that. Menunjukkam phone signal is being used then the red LED. When the phone is not used, the green LED lights up. It does not require external power and can be connected anywhere on the phone line, even mounted inside the phone.
|Phone busy pointer circuits|
List of Components:
R1 = 3.3K 1/4 W Resistor
R2 = 33K 1/4 W Resistor
R3 = 56K 1/4 W Resistor
R4 = 22K 1/4 W Resistor
R5 = 4.7K 1/4 W Resistor
Q1, Q2 = 2N3392 NPN Transistor
BR1 = 1.5 Amp 250 PIV Bridge Rectifier
LED1 = LED red
LED2 = LED green
Others = Wire, Containers, Telephone Cable
This circuit is very simple and easy to make on the board and installed on the phone. Try a series of telephone busy pointer