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Inside Echolink

Inside Echolink. Amateur Radio meets Voice over the Internet Protocol. Ron P. Milione – W2TAP w2tap@arrl.net ron.p.milione.ctr@us.army.mil. Overview. VoIP Concepts and Terminology Analog, Digital, Samples, Buffers Packets, Client/Server, TCP/IP Ham VoIP Projects

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Inside Echolink

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  1. Inside Echolink Amateur Radio meets Voice over the Internet Protocol Ron P. Milione – W2TAP w2tap@arrl.net ron.p.milione.ctr@us.army.mil

  2. Overview • VoIP Concepts and Terminology • Analog, Digital, Samples, Buffers • Packets, Client/Server, TCP/IP • Ham VoIP Projects • Access, Modes, Connecting, Audio Quality • Topology, Users, Is this ‘Ham Radio’? • EchoLink Software Graphical User Interface • Setup, Radio, Computer • Modes, Configuration • Radio Interfaces • W2LV - Live Node Demo • Good Practices • Common Problems

  3. What is VoIP? • Convert Voice to Digital 1’ 0’s (A/D) • Compress Digital Data (Encode) • Buffer digital sample data into packets • Send packet buffers via Internet Protocol • Receive and assemble packet buffers • Uncompress Digital Data (Decode) • Convert Digital 1’s 0’s to Voice (D/A)

  4. What is THIS Echolink? • EchoLink uses VoIP (Voice Over Internet Protocol) to allow licensed Amateur Radio Operators to communicate with other Amateurs via the Internet. • It is primarily a Windows based application and is offered free of charge at http://www.echolink.org. • There is also a new EchoLinux and EchoMac available. • It was developed by Jonathan Taylor (K1RFD) in 2002 (He received Hamvention 2003 Special Achievement Award).

  5. A/D – D/ATerms and Concepts • Analog <> Digital • Continuous <> Discrete • Air Pressure <> Volts • Sampling Rate • Freq. (KHz) 8, 11, 22, 44 • Unit time (secs) • Sampling Bits • Quantization (#) 2^8, 2^16 • Dynamic range (dB) 50, 98 • Nyquist Theorem • Sample Rate >= 2 x Freq.

  6. Encode / DecodeCompress / Decompress • Codec Types • GSM (E/L 8kbps) • uLaw • aLaw • ADPCM • Function • Don’t send dead air • Combined similar values • Save space and time

  7. What Modes Are Available? • EchoLink can be operated strictly between two computers connected to the Internet using the PC soundcard with Speakers and a Microphone. • EchoLink can be interfaced to a standard FM transceiver as a “simplex link” from your home QTH. • EchoLink can be interfaced to a VHF or UHF repeater for more coverage.

  8. Internet and IP • Hosts • Routers • Dotted Decimal Addresses • Transport (TCP/UDP) • Source & Destination Ports • Data / Buffers • Checksum

  9. Connecting via VoIP • Two methods / implementations • Client / Server (Middleman) • Client is Authenticated (Callsign / Password) • Client Requests Users List ( Callsign, IP Addr.) • Client Makes Connection to User • No Central Server (Client to Client) • Client Must manually obtain remote IP Addr. • Client Makes Connection to User

  10. Amateur Radio VoIP Projects • EchoLink – http://www.echolink.org/ • IRLP – http://www.irlp.net/ • CQiNet – http://cqinet.sourceforge.net/ • WIRES II – http://www.vxstd.com • eQSO – http://www.eqso.net/

  11. Echolink Overview • Link Radio Amateurs via the Internet • PC-PC Users, PC-RF Gateways, RF-RF • Simple Password Access to Server • “By Hand” Callsign check for Password Validation • GSM Vocoder 8kbps/user • Lower Voice Quality (Dial-up or Broadband ISP) • Multiple Connections per Node Possible • Bandwidth Limited (Broadband Required for Conf) • Node Information (http://www.echolink.org/logins.asp) • 4715+ Active Nodes Worldwide • 1050 Users, 1464 Links, 1113 Repeaters, 192 Confs.

  12. VoIP Network Topology 209.176.50.1 68.54.3.2 W2TAP W2LV 128.10.60.73 WA2CDL 212.50.33.5 141.9.5.102 W4AJX

  13. PC to PC

  14. Sys Op Mode

  15. Simplex Link

  16. Repeater Link

  17. PC Users, Links, Repeaters

  18. EchoLink - The Software • Windows • Mac • Linux • Sysop • User

  19. And now -- The Software… • Here is the main Screen, listing the Stations currently on the Link, by Country, Call Zone etc. The Bottom of the Screen shows the current Transmit and Receive Audio levels in a colored bar graphic.

  20. Basic Setup • The first thing to do after installing the software is to configure your Station Setup. The first time you use Echolink, you will have to wait to be validated, before you are connected to the EchoLink server.

  21. Audio Setup This includes your Audio details, for the PC Speakers and Microphone.

  22. Connection Setup This Screen allows you to configure the various Internet connections you are willing to accept.

  23. The Two Pc Audio Screens This is the Output This is the Input

  24. Interfaces • Types • Commercial • Homegrown • Function • Isolate • Attenuate • Match • Key PTT • COR

  25. Commercial Interfaces

  26. DIY Interface Schematic

  27. W2VL • Echolink node #487981 • CallNodeLocation/ConnectionStatus W2VL-R 487981 LIMARC, GlenOaks, NY (1) ON • 40.7470463 -73.7115199 • 146.850MHz (-) Offset Duplex • Supports 4+ simultaneous users • Access is Open 24/7 • IRLP ID: 4438

  28. W2KPQ • Echolink node #503075 • CallNodeLocation/ConnectionStatus W2KPQ-R 487981 LIMARC, SELDEN, NY (1) ON • 40.8664873 -73.0356625 • 147.3750MHz (+ offset) Duplex • Supports 4+ simultaneous users • Access is Open 24/7 • IRLP ID: 4478

  29. Control Operation • 3 Levels of Control • DTMF over Link Frequency • HTTP Web Interface • Direct PC Keyboard • Control Operators • LIMARC • WA2CDL - Andy

  30. Node DTMF CommandsGiven as an example • Status – 08 • Connect – 4, 5, 6 digit node number • Echo Test Server = 9999 • short cuts, ex: *90 = WA2CDL-R • Disconnect - # • Reconnect – 09 • Help File -*411

  31. Good Operating Practices • Identify Yourself • When connecting • When sending DTMF • Pause, Wait, Listen • Use DTMF Status Command 08 • Rag chewers beware • 3 minute timeout

  32. Common Problems • Connection Timeout • Disconnects • Audio issues • Broken • Garbled • Drop outs

  33. W2VL REPEATER

  34. W2KPQ REPEATER

  35. Local EchoLink Nodes List

  36. Local EchoLink Nodes Map

  37. Question?Tnx & 73 ! Ron Milione Ph.D. w2tap@arrl.net ron.p.milione.ctr@us.army.mil

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