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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

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November 1998 - 2December 1999 +10= 12June 2000 +20 = 32

December 2000 +29 = 61June 2001 +61 = 122

December 2001 + 199 = 321June 2002 + 236 = 557

December 2002 +263 = 820January 2009 + 668 = 1488

IRLP Growth

database records 2009.01.31

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World IRLP Snapshot

1109

21595 55 21 18 13 11 55

445

15454 2 6 3

0200400600800

10001200

USACan

ada

Austra

lia + N

ew Z...

Englan

dMex

icoJa

pan

Puerto

Rico

Scotla

ndOthe

r

Country

20092003

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VE3MIS IRLP NodeRF Components

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 (mockbuild@builder4.centos.org) (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).

Receiving Audio

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2074 - 2093 Audio (bi-directional UDP)15425-7 IRLP Control/Update (TCP)

22 SSH Remote Admin (TCP)

Outbound ports used: 80 (http) for updates

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

• Continues to function if servers fail

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Two ways to make contacts

Point-to-Point

and

Reflectors(like chat rooms -- multiple nodes connected

together, hearing audio from one node at a time)

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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

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Thank You