Projetos de Circuitos de Telefonia e Intercomunicação

1. 1-line telephone status indicator (PDF)
2. 300 baud modem circuit schematic
3. 4-line telephone status indicator (PDF)
4. Assorted telephone circuits
5. Caller ID decoder
6. Caller ID decoder part 1
7. Caller ID decoder part 2
8. Cut Phone Line Detector
9. Cut phone line detector
10. Detecting a telephone RING
11. Digisound ring modulator
12. Digital/Standard Phone Line Tester
13. DTMF decoder / logger
14. DTMF Generator/Decoder
15. FM Telephone Bug
16. FM telephone bug
17. Greek telecard reader
18. Hold function for Telephone
19. Home made PBX / PABX
20. Incoming call indicator
21. Infinity Transmitter Schematic and Plans
22. Interface cables for various cell phones
23. Line in use indicator (PDF)
24. NCDS Interface Schematic for Nokia 3110, 8110, 8110i
25. Phone Busy Indicator
26. Phone in-use
27. Phone In-Use Light
28. Phone Line to Audio
29. Phone Off-Hook Indicator
30. 'phone rang' indicator light
31. Phone ring circuit schematic
32. Phone to audio interface
33. Phone-In-Use indicator
34. Ringing Phone Light Flasher
35. Simple circuit to connect telephone equipment to audio mixer
36. Simple Phone Tap
37. Talking phone dial monitor
38. Taxi phone automatic dialler
39. Telephone Audio Interface
40. Telephone autodialler
41. Telephone Hold Button
42. Telephone in use light
43. Telephone interfacing / caller ID using a PIC microcontroller
44. Telephone In-Use LED Indicator
45. Telephone In-Use Relay Circuit
46. Telephone Line Monitor
47. Telephone line simulator
48. Telephone music on hold box
49. Telephone privacy adapter
50. Telephone Recorder
51. Telephone recording circuit
52. Telephone ring controlled relay
53. Telephone Ring Generator Using 60Hz Power Transformer
54. Telephone Ring Generator Using Switching Power Supply
55. Telephone ringing circuits
56. Universal telephone hold
57. Use old phones as an intercom