What is IRLP?

• IRLP (Internet Radio Link Project) is a method to interconnect different two-way FM radio transceivers together worldwide using the Internet as the backbone.

What is an IRLP Node?

• An IRLP Node is a radio receiver and transmitter, which is interfaced to a PC running IRLP “Node" software connected to the Internet.

Common Node Types

IRLP Nodes and Reflectors in North America

IRLP European Nodes

What is an IRLP Reflector?• A reflector is a PC on the Internet

running IRLP "Reflector" software.

• The reflector has no radios connected to it. It allows multiple individual IRLP nodes to simultaneously connect to it, so all the individual IRLP nodes are now tied together, forming a single multi-user conference connection.

9000 REF9000 Vancouver BC Canada 9070 REF9070 Alaska Reflector AK USA 9100 REF9100 Toronto Reflector ON Canada 9200 REF9200 Indianapolis IN USA 9210 REF9210 Raleigh NC USA 9250 REF9250 Western Reflector NV USA 9300 REF9300 Saskatoon Reflector SK Canada 9310 REF9310 Fredericton NB Canada 9350 REF9350 LAX - [WALA] Hub CA USA 9400 REF9400 Quebec City - GSM Only QC Canada 9450 REF9450 Dallas TX USA 9500 REF9500 Sydney - Virtual PUB NSW Australia 9600 REF9600 Philadelphia PA USA 9610 REF9610 St. John's - GSM Only NL Canada 9700 REF9700 Lancaster LANCS England 9730 REF9730 Indiana Regional IN USA 9800 REF9800 Scandinavian Reflector Angered Sweden

How Does IRLP Work? • The microphone and speaker audio, and

the PTT and COS lines from a transceiver, are connected to a PC sound card and IRLP interface card.

• The IRLP software makes the Internet connection between two IRLP nodes or one IRLP node and a reflector.

• The receive and transmit audio is sent via VoIP (Voice over IP) data streams.

How it Works…•When IRLP nodes are connected, audio from the sending node is transmitted on the receiving IRLP node, pending a small Internet propagation delay at the receiving node.

•When your IRLP node is connected to a reflector, when you transmit, your voice is transmitted on all IRLP nodes connected to the reflector.

Anything Unique About Using IRLP? You will need to wait ~2 seconds before talking afterpressing your microphone’s PTT (Push-To-Talk) button. This will give time for the Internet links to sync up and prevent the first word or two of your transmission from being chopped off.

When the other station finishes talking, wait until after you hear the courtesy beep before you press your PTT. The repeater IDs every 10 minutes and if you “Quick Key” your PTT, the ID will over-ride your transmission.

Also by not “quick keying,” you allow other stations a chance to break-in.

Occasionally internet packets are lost or arrive late. These cause dropouts or breaks in the received transmission.

How Does IRLP Work ?• IRLP uses Voice-Over-IP (VoIP)

software called Speak Freely. It is very similar to other VoIP software packages (such as Microsoft NetMeeting and VocalTec Iphone) except... It runs under Linux.

• Linux is used for IRLP because it is reliable, programmable, efficient, and functional.

The VoIP Concept for IRLP

1. Sample the audio using an analog to digital (A/D) converter. The A/D converter used is a standard PC sound card. This creates a 8-bit digital stream of raw audio.

2. Compress the audio by using an 8-bit algorithm to reduce the size of the stream by a factor of two.

3. Split the stream into packets.

4. Transmit the packets.

5. Uncompress the packets into an 8-bit raw audio.

6. Play the audio stream through a digital to analog (D/A) converter (your sound card).

Some Interesting NodesOthers can be found at: http://status.irlp.net/statuspage.html 

• 2040 VE2CRA Ottawa Canada • 2050 VE1NSG Halifax Canada• 4970 WA1ZVZ Merritt Island FL• 5470 8P6AW Bridgetown Barbados • 5510 MM0GEQ Edinburgh Scotland • 5515 DB0VOX Nuremberg Germany• 5600 GB3LV London England• 6800 VK8ZMA Darwin NT Australia • 6950 ZL1BQ Auckland New Zealand • 7000 J73D Roseau Dominica • 7995 VP9/VE3KXX Smiths Parish -- Bermuda • 8700 ON0GRC Gent Belgium • 8880 KC4USV McMurdo Station – Antarctica

Idaho FallsNODE 3372

Currently, there is just one IRLP node here in Idaho Falls:

• 446.500 (100hz Tone Required) Red Lion Simplex

• 14x.xxx Red Lion (in the very near future!) This will require a tone as well and will be Simplex.

Common Error Messages

“The node you are trying to connect to is being used locally.”The node you are trying to connect did respond because it’s being used locally. “The call attempt has timed out the connection has been lost.”The node called is NOT responding.The Internet retry count might have exceeded limit.The node is temporarily off-line. “The connection has been lost.”(During a conversation)The Internet retry count might have exceeded limit.The node has temporarily gone off-line.The Internet might be very busy and causing excessive message delays.The other end terminated the link. ”Busy Audible Tones”The node you are trying to connect to responded, however it’s currently in use.You can check the active node status page to see where it is connected. Visit http://status.irlp.net/ “The node you tried to call does not exist. Please check the code and try

again.”You entered an invalid four digit node number.

For additional information visit http://www.irlp.net/

Equipment on the Red Lion

• UHF - Alinco DR-435T

• Dell Computer

• VHF – Radio still to be determined

• Microtel Computer