Telephone Line Ring and Indicator

Description

It is a relatively simple circuit, with which we can have optical and sound clue, when we have telephone ring in the line of telephone. The calls in the line, are changed in pulses of frequency 400 HZ from the IC2, in exit 3. Then via the IC4, after they are strengthened at two times, they can be drive to the entry of amplifier and a loudspeaker, so that we hear the ring, in what level we want. The desirable level of sound is regulated by the trimmer TR1 that if we want can be replaced with pontesometer. With the led LD1 we have optical clue, of rings. Simultaneously via the IC3 it can become control, exterior circuit, adapted in the needs each virtuous.

Scehmatic

Part List

• R1-3-13=4.7Kohm
• C1-7 =100nF 630V
• Q1-2 = BC550C
• R2-11-12 =1Mohm
• C2=4.7nF 63V MKT
• IC1-3 =4N35 - CNX38
• R4 =1Kohm
• C3 =220uF 25V
• IC2=LM555
• R5 = 2.2Kohm
• C4 =33nF 63V MKT
• IC4 =TL071
• R6 = 33Kohm
• C5 =220nF 63V MKT
• LD1 =LED 3-5 mm
• R7 =390Kohm
• C6 =10uF 25V
• TR1=10Kohm Trimmer or Pont.
• R8 =820ohm
• C8 =47nF 63V MKT
• CON1 =4 pin connector
• R9 =22Kohm
• C9 =100uF 25V
• CON2 =4 pin connector
• R10 =1.8Kohm
• D1-2 =20V 1,3W Zener
• R14 =10Kohm
• D3 =1N4002