Ringers

Telephone Ring Indicator Circuit

A neon lamp can easily be added to the phone line to act as a ring indicator...

Telephone ringing detector

With the 555 timer connected as a multivibrator and an opto-isolator, ..

Telephone tone ringer

This is a complete telephone bell replacement circuit with minimum external components with on-chip diode bridge and transient protection..

Telephone or extension tone ringer

This circuit uses ML8204/ML8205 devices..

Telephone in-use indicator

This circuit functions as a line-current sensor and can be connected in series with either of the phone lines. For the circuit to indicate an "in use" status for all phones on a single line, it must be connected in series with the phone line before, or ahead of all phones on the line...

Plug-in remote telephone ringer

This device consists of a ring detector connected to the telephone line. When the telephone rings, the ring detector impresses high-frequency pulses on the ac power line...

Extension Phone Ringer

The ac ringing voltage (typically 40 to 90 V at 26 Hz) is rectified by U1, the tone-ringer IC, and is used to drive ..

Remote-telephone-ringer

The two neon bulbs will light when more than 100 V is across the ringing circuit. The bulbs provide line isolation between the unit and the telephone line. Finally, they act as a voltage divider for the bridge rectifier made up of D 1 through D4. That voltage divider creates a positive voltage that is then applied through D5, is filtered by R2, R3, and C2, and causes Q1 and Q2 to conduct. ..

Phone auto answer and ring indicator

Ring detect circuit for automatic phone answering or tone generation..

Call Tone Generator

Amateur VHF relay stations are normally actuated by a 1750-Hz call tone. This might give problems if the relevant sendi..

Tone ringer

The MC34012 tone-ringer chip derives its power by rectifying the ac ringing signal. That signal is normally at 20 Hz and measures between 70 and 130 volts rms. It uses that power for the tone generator and to drive the piezoelectric transducer. The sound that is produced is a warble that varies between two frequencies, f0/4 (f0 - 4) f0/5. The clock, or fundamental, frequency, f0, is generated by a relaxation oscillator. That oscillator has R2 and C2 as its frequency.....

High isolation telephone ringer

The diode rectifies the ringing signal to supply the operating power to the audio relaxation oscillator made up of LI, L2, Rl, R2, and C. Moreover, L2 together with Ql acts as an opto-isolator, totally isolating the telephone line from the rest of the circuit. The oscillator audio frequency is optically coupled to the photo-Darlington which drives Q2 and thus the speaker...

Telephone Bell Simulator Circuit

This circuit is intended for use in a small private telephone installation. The ringing tone sequence is 400 ms on, 200 ms off, 400 ms on, 2 ms off. In the accompanying diagram, N1 and N2 form an oscillator that operates at a frequency of 5 Hz, which gives a period of 200 ms. The oscillator signal is fed to two decade scalers, which are connected in such a manner (by N3 and N4) that the input signal is divided by 15. The second input of N4 can be used to switch the.....

Tone ringer II

The XR-T8205 Tone Ringer is primarily intended as a replacement for the mechanical telephone bell. The device can be.powered directly from telephone ac ringing voltage or from a separate dc supply. An adjustable trigger level is provided with an external resistor...

Ringer-relay

When the phone rings, the ring signal from the telephone company lights a neon lamp within a CLM3120 optocoupler. That causes a drop in the resistance of the CdS cell output of the device, turning on transistor Ql. ..

Electronic phone bell

The speaker emits a distinctive warble tone when ring pulses are applied to the phone line. Use this circuit as a remote bell or disconnect the phone"s ringer for direct use. Rl adjusts the duration of the output; R2 and R3 control the tone"s duty cycle and frequency. The transistor is a general-purpose NPN photodevice..

Musical telephone ringer

The heart of the circuit is IC1, General Instrument's AY-3-1350 melody-synthesizer IC. IC2 is a TCM1512 telephone ring detector IC that is powered by the telephone line. The circuit's operation begins when IC2 senses a ring pulse on the telephone line. The detector (internally) rectifies the ring signal and then outputs a voltage to relay RY1 (an SPST reed-type relay with 5 volt contacts), causing its contacts to close. That pulls pin 12 (the ON/OFF control) of IC1 low.....

Ring-detector

This circuit detects the 20 Hz, "" 86-V rms ring signal on telephone lines and initiates action in an electrically isolated circuit. Typical applications would include automatic answering equipment, and interconnect/ interface and key systems. The circuits illustrated are bare bones circuits designed to illustrate concepts. They might not eliminate the ac/dc ring differentiation, 60-Hz noise rejection, dial tap rejection, and other effects that must be considered in.....

Telephone Ring Converter Circuit

The circuit is based on the TCM1506 ring detector/driver integrated circuit. It is a monolithic IC specifically designed to replace-the telephone`s mechanical bell. The chip is powered and activated by the telephone-line ring, which can vary from 40 to 150 V rms at a frequency of from 15 to 68 Hz. No other source of power is required. Again, referring to the figure shown, CI through C5 are placed in parallel to form a 0.5- capacitor that conducts the ac ring voltage to.....

Remote ring extender switch

The circuit can operate lamps and buzzers from the 120 V, 60 Hz power line while maintaining positive isolation betweenthe telephone line and the power line..