1 Internet Radio Linking Project Internet Radio Linking Project (IRLP) + (IRLP) + Portions of this presentation courtesy of WW4M, KD4RAA, VE3SY, VE7LTD, VK3JED with permission Presentation for the Mississauga Amateur Radio Club Mississauga Amateur Radio Club by Robin Stubbs/VE3VVS & John Lorenc/VA3XJL April 9, 2009
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Internet Radio Linking Project Internet Radio Linking Project (IRLP) +(IRLP) +
Portions of this presentation courtesy of WW4M, KD4RAA, VE3SY, VE7LTD, VK3JED with permission
Presentation for the Mississauga Amateur Radio ClubMississauga Amateur Radio Club
by Robin Stubbs/VE3VVS & John Lorenc/VA3XJLApril 9, 2009
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PC -or- Radio Access:• eQSO (Windows)• iLink (Windows)• WIRES (Windows)• EchoLink (Windows, Mac or
Linux)• D-Star
Radio-only Access• IRLP (Linux)
Ham Radio - Internet Linking
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Internet Radio Linking Overview
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The Internet Radio Linking Project (IRLP)
• Uses the Internet to link distant radio sites
• Gives global coverage to normally localized VHF and UHF frequencies
• Enables minimally equipped stations to communicate globally
• Allows end user control of links via their radio’s DTMF (Touchtone) keypad
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Created by Dave Cameron VE7LTD of Vancouver, BC
Dave was frustrated with the unreliable operation of Windows-based Iphone and
turned to Linux.
Iphone and other systems use VOX. IRLP uses COS.
IRLP is radio-access only.
The Internet Radio Linking Project (IRLP)
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Dave VE7LTD and Pete VK2YXDave VE7LTD and Pete VK2YX
GE Phoenix link radio operating simplex at 441.725 MHz at club stationRepeater controller cardUHF Yagi antennas at club station and repeater site
IT HardwareIntel 800 MHz, P III Processor192 MB RAM10 GB IDE Hard Drive, CD-ROM, 3.5” floppy, 2 USB 1.1 ports3com 3c905c Ethernet adapterSoundBlaster 16 audio cardIRLP Board 3.0 (interfaces to a standard PC parallel port)UPSBell Wimax high speed Internet connectionJuniper Networks Netscreen 5GT firewall appliance
IT SoftwareIRLP 7.02 based on Centos 4.4 with Updates distribution (for those that may be interested, the install script output reports: Linuxversion 2.6.9-42.0.10.plus.c4 ([email protected]) (gccversion 3.4.6 20060404 (Red Hat 3.4.6-3)) #1 Tue Feb 27 16:27:24 EST 2007)
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IRLP Control Board
Does COS, PTT & DTMF
DB9 IRLP to Radio Interface
LPT1 to IRLP Jumper Cable
Custom Centos CD-ROM
Custom IRLP Software
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v.3 IRLP card features surface-mount components
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VE3MISIRLP Node 2998
EchoLink Node 404792
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What Happens During a Call?
Notes from Dave Cameron, VE7LTD
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DTMF Decode• DTMF program monitors COS and DTMF• Once detected DTMF sequence passed
to the decode script• Decode script checks custom_decode
for matches• Assuming a call is decoded, call script is
started with the node number as the argument
VE7LTD
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Call Script• Best server is determined by using
find_best_server script• Best server is asked for latest IP of
node being called• If IP received is different from IP in
hosts file, a new hosts file is d/l from best server
• Irlp_call is started, and a TCP connection is made to the called node on port 15425
VE7LTD
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IRLP_CALL / IRLP_ANSWER
• Remote node starts irlp_answer in response to TCP call on port 15425
• PGP security performs a dual challenge to ensure calling node is an IRLP node
• Codec (GSM/ADPCM) is determined• Irlp_call and irlp_answer start speak
freely software on UDP ports 2074 and 2075
VE7LTD
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During the Call
• Irlp_call and irlp_answer send keepalives in the background. If keepalive fails, the connection drops (every 15 sec)
• Irlp_call and irlp_answer keep open info channel to pass dtmf regeneration info, disconnect/timeout message
VE7LTD
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Disconnects
• Disconnecting node uses TCP info channel to send disconnect message. Both nodes run the off script
• Unexpected drop in the TCP connection prompts reset of IRLP node
• If the timeout elapses, disconnect is sent
VE7LTD
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Audio streaming is enabled when the link radio receives a signal with COS and keys the IRLP
interface card.
The sound card receives the radio’s audio and creates a continuous mono 8-bit digital stream
of raw audio at 8000Hz (64k bps).
Speak Freely’s sfmike program compresses the audio stream by a factor of two (32k bps)
using an audio compression algorithm (codec).
Sending Audio
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The audio is split into packets, which are transmitted over port 2074 using a User
Datagram Protocol (UDP) stream.
UDP does NOT confirm the reception of packets - it "fires and forgets"
Sending Audio …
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Speak Freely’s sfspeaker receives the packets on port 2075 and rejoins them into an 8-bit ULAW
stream. .
Next the ULAW stream is uncompressed back into an 8-bit raw stream of audio.
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The raw audio is streamed through the digital to analog (D/A) converter (the output device of
your sound card). .
The IRLP interface card keys the radio when the audio stream is present (live -- no buffering).
873 or 8873 (rsync) for downloading updates10000 (for IP determination)
parallel port set to "standard" or "compatible" mode, not to ECP, EPP or bi-directional
Ports Required
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Some IRLP Network Details512-bit bi-directional PGP authentication ensures connections only with other IRLP
nodes.
Redundant servers support IRLP-BIND(DHCP isn’t a problem) as well as download of pgp key rings, software updates, and station
ID wavfiles.
IRLP accepts commands from keyboard or via DTMF (dual tone multi frequency, i.e.
“Touchtones”)
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IRLP Admin• Regulations prohibit unlicensed people using
amateur frequencies.• IRLP links are accessible only on amateur
radio frequencies within range of a node. No direct Internet access.
• OpenSSH (Putty) used for remote administration.
• Linux packages updated automatically (up2date, autorpm, apt).
• Cron jobs to automate functions– Node disable and enable during MARC Tuesday net
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IRLP Scripting• The IRLP software is composed largely of
bash shell scripts.• Flexible: easily customized to suit local
needs.• Almost anything that can be run from the
console can be controlled via radio.– Morse Code ID using MIDI or wav (per FCC legal
requirements)– Node status (link off/on and where linked to)– Time of day (talking clock)– Weather reports, Amber Alerts– Local Announcements– Download and play radio news programs from internet– Random dialing– *69 / “Call Waiting”
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IRLP Advantages
• User Flexibility - Custom Scripts• Accessible only by radio
• Security• Stability of linux OS
• Superior audio; COS (not VOX)• Cost: Linux is free, will run on old PCs
IRLP Reflectors• Enable multiple nodes to link together into a
network – number limited only by bandwidth.• Running a reflector requires bandwidth (32
kbps per connected node) to handle the multiple data streams. Most reflectors are
hosted by ISPs (like Inflow) who often donate the bandwidth.
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EchoLink
• Jonathan Taylor, K1RFD, won the Dayton Hamvention's Special Achievement award, 2003, for writing and developing EchoLink and EchoStation.
• EchoLink software is available for Windows, Macintosh OS/X and Linux, free of charge.
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EchoLink Operation• Nodes, Links, Repeaters!
– Each connected station has a unique station ID called a “node number” that is assigned automatically.
– There are several different node types:• Users: Stations that are using a personal
computer.• Links: Stations with computers running EchoLink
interfaced to a radio transceiver. These stations are designated by their callsign followed by “-L”.
• Repeaters: Stations with computers running EchoLink interfaced to an FM repeater through a repeater controller or via remote transceiver. These stations are designated with their station callsign followed by “-R”
• Conferences: Special interest “chat rooms”
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EchoIRLPThe Integrated Dual Node
• Tony Langdon/VK3JED operated first EchoIRLP node in Australia, 1998
• Uses one machine and interface to allow connectivity to both systems.
• Lockouts between IRLP and EchoLink to prevent unintentional cross links.
• Uses tbd (theBridge) as a local gateway between IRLP controlling the hardware and the EchoLink network.
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EchoIRLP Block Diagram
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The Future
• Internet linking continues to grow – over 1475 IRLP nodes on the air.
• Advances in technology will improve performance of links.
• Other digital technologies.–WIRES II, D-Star, …
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•MARC website- www.marc.on.ca
•IRLP in General- www.irlp.net- groups.yahoo.com/group/irlp/
•EchoLink- www.echolink.org•Radio Amateurs of Canada- www.rac.ca
More Info
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How do I use it?From the VE3MIS 2 m
Repeater
Disconnects7 3
http://www.echolink.org/links.jspConnects to EchoLink NodeXXXX
# X X X X
http://status.irlp.net/Connects to IRLP Node XXXXX X X XNode Listings and StatusFunctionDTMF