The IRLP System comes in 2 Flavors:
1 - Simplex Link Radio
2 - Repeater
There are always radios involved at both ends of an IRLP link connection.
The IRLP system is a system that allows for only radio to radio connections. This means that there is a radio involved at both ends of the link and the medium used to complete the connection between the two radios is the internet instead of the traditional RF links we used back in the 80's that limited the link distance to a few hundred miles before the link became unwieldy.
The IRLP system does not depend on central servers in order to complete a link as the connection is peer to peer meaning the connection is between the local host computer and the destination computer. There is always a current list of IP Nodes stored on each IRLP computer so the system should function even if there is a loss of central ip resolution servers.
In IRLP there are two types of links available, Repeater or Simplex Link. The local computer used for IRLP can be connected to a repeater via RF link as in our case with the 443.650 repeater, or can be connected to the repeater via hardwire cable if the computer is co-located at the repeater site. If the latter is the case then the system can be run in full duplex and the computer can be controlled from the repeater input at all times not just when the tail of the repeater drops.
If the system is set up as a simplex link then the node computer acts like a normal remote user and to shut down a connection we need to wait until the other end stops transmitting (talking) before we can give a control command.
On IRLP there are two types of connections. One is node to node and the other is by connecting to a reflector. A reflector is like a traditional RF HUB Link Repeater but located in cyberspace and has no radio but is just a computer running special reflector IRLP software.
This computer is connected to a very high speed internet connection that has plenty of upload speed and is usually located in a data center.
A reflector requires the opposite type of internet connection than your typical home internet and requires all it's speed on the upload, not the typical download. A reflector is a one connection inbound and many outbound. It basically repeats what one station is saying out to many stations that are listening and participating in a sort of round table. Again the analogy of the Hub Repeater applies here.
There are 29 IRLP reflectors with 10 channels each so there are 290 separate channels that can be used by nodes that want to participate in multiple node connects like nets, emergency communications, rag chewing, etc.
The main IRLP website is located at: http://www.irlp.net/
To view in real time the reflector status and who is connected to where, go to: http://status.irlp.net/
Node to Node is a much simpler connection and is a direct connection from our computer to the destination computer which is connected to either a repeater or a simplex radio. Again, IRLP is always radio to radio at the user ends.
Making a Call:
To make an IRLP call you would determine your destination repeater/link node number. All IRLP nodes have a 4 digit code.
The above location gives a real-time list of the IRLP Network Summary at this point in time. The list updates every few seconds.
This above url displays the real time list of active nodes. This means if the node is view-able then it should be reachable if the Status of the node shows IDLE. If you should dial a node number and the other end is in use you will get back a voice announcement that the node is busy and to try calling back later. The destination node will also get a voice message telling them that node XXXX was trying to call them.
We have added a few extra optional features to the local 8317 N4FOB computer like:
Time announcement every 1/2 hr between the hours of 6:00am and 11:00pm
Time announcement can be dialed at will with *0 command.
Last call waiting can be dialed at will with the *69 command.
Dialing an IRLP repeater:
Determine from the IRLP node list where you wish to connect, key up your radio, announce your callsign and intention to use the repeater and dial the destination 4 digit node number. Release your ptt and wait for the call to go through. Make sure you wait at least 5 seconds once the repeater tail finally drops before you transmit as you don't want to talk over top of someone or into an existing conversation at the other end. Once you have waited long enough, key your mike and count to 2 before speaking as you need a small bit of delay after keying up to allow the link to key up the other ends transmitter so your first word will not be cut off. You will soon get the hang of it.
The Echolink system comes in 3 flavors:
-User - This is a Ham on a computer somewhere using a headset mike. (No Radio Involved at his end)
-L Link - This is a Ham on a link radio normally on a simplex channel either on vhf or uh
-R Repeater - This is a Ham on a Repeater similar to the reflectors used in the IRLP System.
Echolink in our case is a mere addition of extra scripts added to an existing fully functional IRLP node. These scripts allow the IRLP computer to also make an receive Echolink calls but not cross link the two systems. If an Echolink call is in progress the IRLP side will be busy and vice versa. There is no additional hardware required on an IRLP node to make it into an EchoIRLP node which can handle both systems. It costs nothing to add echolink to the IRLP node and gain an additional set of functions and thousands of echolink nodes additionally become available.
Echolink is a system with a different philosophy than IRLP in that Echolink allows computer to computer connections to be made so you could be speaking to a Ham on a laptop sitting in a Retirement Community where he cannot install antennas and has only a computer available. This opens up a whole new world to Hams in this type of situation not to mention the capabilities gained for emergency communications by being able to set up a laptop at any hot spot or internet connection and be able to communicate through the repeater system. Another way is by using an Apple Ipad or SmartPhone with the Echolink App and you can also then access the repeater from any internet system in the world. Multiple echolink connections to the node from anywhere in the world are possible in an emergency and are limited only by the upload bandwidth of the host internet connection and it's robustness.
Remember that there is stringent call sign authentication in place for both the IRLP and the echolink system so non-hams cannot access the repeater from the internet. Irlp actually uses a pgp key authentication system during every call before a call is connected and able to progress to a completed connection.
An echolink number consists of anything from a 4 digit destination number up to 6 digits including a pre-access digit.
This then means that echolink dialing is a bit more of a challenge as the minimum digits dialed will be 5 and the maximum would be 7 to gain access to a destination Echolink node.
I can remember about 7 or 8 IRLP node numbers but have trouble remembering more than 3 Echolink numbers. Also it is a real challenge to dial these while mobile.
There is a solution to this problem if there are favorite echolink numbers that are commonly dialed on the node I can install a code translation that will dial the destination node with as little as two or three numbers and using the A to C part of the TT Pad to make it even easier to remember. So your favorite Echolink station could be a simple eg. C3 code.
Making an Echolink Call:
To dial an echolink call you simply key your mike and enter the pre-access digit followed by the destination node number.
The pre-access digit for node 8317 is # so if you were dialing the destination node K4CVL-R in Bradenten Fl node number 395804 you would key your mike and press #395804
Lastly, to disconnect the repeater from either an IRLP or Echolink connection you simply dial 73 on your touchtone pad.
Hope you enjoy using the EchoIRLP VoiP system.
73 from Klaus Rung ve3kr