1. Group #13 West Virginia University - LCSEE Department. Group Members: Bahassan, Maher Rosendale, Matt Rossetti, Anthony

2. Introduction What is a repeater? What is DTMF?

3. User A User B Transmitted 146.76 MHz

4. Retransmitted = 146.76 Transmitted 146.16 MHz User A User B

5. DTMF = Dual Tone Multi Frequency COR & PTT

6. Inside The Simplest Repeater

7. 146.16146.76 Inside A Real Repeater

8. Controller Requirements User changeable defined call sign - ID’s every ten minutesUser changeable defined call sign - ID’s every ten minutes Telephone InterfaceTelephone Interface Inhibits telephone communication after 3 minutes (exception emergency calls)Inhibits telephone communication after 3 minutes (exception emergency calls) Remote accessing of controllerRemote accessing of controller Watchdog TimerWatchdog Timer Courtesy Tones (Half-Duplex)Courtesy Tones (Half-Duplex) RF shieldingRF shielding Hang TimeHang Time Rapid Transmissions (Kirchunking)Rapid Transmissions (Kirchunking)

9. Should not have inappropriate interference with transmitter and receiver!!!

10. New Technology Auto-Patch Smart Identification Remote Shutdown “Kirchunking” Optically Coupled Motorola Microprocessor Relays

11. Opto/Audio Isolators DTMF Decoder DTMF Encoder Tone Generator Telephone Audio AmplifierAudio Amplifier MicroprocessorMicroprocessor MemoryMemory Transmitter/ReceiverTransmitter/Receiver

12. Projected Architecture

13. Transmitter Activation Start Is COR HIGH? NO Set PTT HIGH Is COR HIGH? Yes Courtesy TonesStart Hang Time Set PTT LOW Yes NO

14. Identification/Courtesy Tones 555/556 Timer Tone GeneratorTone Generator PIC Voice Chip “W8CUL /R”

15. Remote Access –DTMF Tones Valid Password 1 = Alternates Transmitter State “Off” - “On” 0 = Permanent Off –Telephone Valid Ring Count 5 = Alternate Transmitter State 4-Sec 2-Sec 75 V RMS @ 20HZ

16. Initialize Telephone Call Possible Band-Pass Filters

17. Callsign Programming Interrupt (PB7:PB4) Begin - End = ENTER

18. Micro-Controller vs. Personal Computer Versatile Low-power High-Speed Low-Cost Wide Operating Temperature Ranges

19. PIC16F877 System Features 40-Pin CMOS Flash Microcontroller Operating Speed: DC-20MHz 10-bit Multi Channel Analog-to-Digital Converter Interrupt Capabilities = 14 Sources Temperature range: -40C to 85C Three Timers (Watch Dog) 256 * 8 Bytes of EEPROM 8K * 14 Words of Flash Extensive Features

21. Overview Complete System packageComplete System package –Compatibility –Simple –Affordable –Functional –Reliable

22. Group Members: Bahassan, Maher Rosendale, Matt Rossetti, Anthony Marconi Special Thanks To: Dr. Nutter Dr. Palmer