Transcript EchoLink

EchoLink
Amateur Radio meets
Voice over the Internet Protocol
Andy Zwirko – K1RA
http://go.to/andyz
[email protected]
Overview
VoIP Concepts and Terminology
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Analog, Digital, Samples, Buffers
Packets, Client/Server, TCP/IP
Ham VoIP Projects
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Access, Modes, Connecting, Audio Quality
Topology, Users, Is this ‘Ham Radio’?
EchoLink Software Graphical User Interface
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Setup, Radio, Computer
Modes, Configuration
Radio Interfaces
K1RA-L Live Node Demo
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Good Practices
Common Problems
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)
A/D – D/A
Terms and Concepts
Analog <> Digital
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Continuous <> Discrete
Air Pressure <> Volts
Sampling Rate
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Freq. (KHz) 8, 11, 22, 44
Unit time (secs)
Sampling Bits
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Quantization (#) 2^8, 2^16
Dynamic range (dB) 50, 98
Nyquist Theorem
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Sample Rate >= 2 x Freq.
Encode / Decode
Compress / Decompress
Codec Types
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GSM (E/L 8kbps)
uLaw
aLaw
ADPCM
Function
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Don’t send dead air
Combined similar
values
Save space and time
Internet and IP
Hosts
Routers
Dotted
Decimal
Addresses
Transport
(TCP/UDP)
Source &
Destination
Ports
Data /
Buffers
Checksum
Connecting via VoIP
Two methods / implementations
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Client / Server (Middleman)
Client is Authenticated (Callsign / Password)
 Client Requests Users List ( Callsign, IP Addr.)
 Client Makes Connection to User
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No Central Server (Client to Client)
Client Must manually obtain remote IP Addr.
 Client Makes Connection to User
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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/
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)
 2700 Active Nodes Worldwide
 552 Users, 1064 Links, 962 Repeaters, 122 Confs.
VoIP Network Topology
209.176.50.1
68.54.3.2
K1HTV
128.10.60.73
WA3NAN-R
212.50.33.5
141.9.5.102
K1RA
NA3J/0
PC to PC
Sys Op Mode
Simplex Link
Repeater Link
PC Users, Links, Repeaters
EchoLink - The Software
Windows
Mac
Linux
Sysop
User
Interfaces
Types
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Commercial
Homegrown
Function
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Isolate
Attenuate
Match
Key PTT
COR
Commercial Interfaces
DIY Interface Schematic
K1RA-L
Echolink node #199756
Warrenton, VA – FM18cr - ~ 550ft ASL
144.440 MHz Simplex - ~20w
Adelphia Cable ISP - 4Mbps / 512Kbps
Supports 4 simultaneous users
Software version 1.980
Access is Open 24/7
Node Hardware
Radio Equipment
•ICOM IC207H
•20 Watts
•5/8ths vertical @25ft
•12v 20A P.S.
Computer Equipment
•Pentium II – 350MHz
•192 MB RAM
•6 GB Hard Disk
•10baseT NIC
•Linksys D614+ FW
•2000VA UPS
Control Operation
3 Levels of Control
DTMF over Link Frequency
 HTTP Web Interface
 Direct PC Keyboard
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Control Operators
K1RA - Andy
 KZ1AMY - Amy
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Node DTMF Commands
Status – 08
Connect – 4, 5, 6 digit node number
Echo Test Server = 9999
 short cuts, ex: *90 = WA3NAN-R
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Disconnect - #
Reconnect – 09
Help File -*411
Good Operating Practices
Identify Yourself
When connecting
 When sending DTMF
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Pause, Wait, Listen
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Use DTMF Status Command 08
Rag chewers beware
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3 minute timeout
Common Problems
Connection Timeout
Disconnects
Audio issues
Broken
 Garbled
 Drop outs
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Local EchoLink Nodes List
Local EchoLink Nodes Map
Question?
Tnx & 73 !
Andy Zwirko – K1RA
http://go.to/andyz
[email protected]