Indicators and Display
Circuit / Schematic diagram | Description |
Telephone line indicator (circuit on demand) |
Indicated the status of telephone connected to a common line. |
Telephone on/off hook indicator | The circuit gives audio/visual indication of on/off hook and ringing modes. |
Telephone in use indicator | It will allow users to know if the phone is being used and not to pick up the phone. |
Extension free indicator | Indicates if another phone using the same line is free or not. |
Telephone busy indicator | Indicates if any telephone in the same line is busy or not |
Caller Identification | |
Caller Identification 2 | |
Caller Identification 3 | |
Telephone Billing machine | Circuit can be used in PCO for displaying the actual call time. |
Telephone call meter using calculator | Displays the call time and based on simple calculator and COB |
Smart Phone light | The circuit shown here is used to switch on a lamp when the tele- phone rings |
Talking phone dial monitor | Detects the number pressed and speaks the dialed number |
Telephone dial alarm | Microcontroller based. |
Telephone number display | The given circuit, when connected in parallel to a telephone, displays the number dialled from the telephone set using the DTMF mode. |
DTMF Tone Decoder | Displays telephone numbers decoded from tones |