How to convert an IRLP node into Allstar or Allstar and Echolink

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This article describes the process for converting an IRLP node to operate instead on the Allstar Link, app_rpt, Asterisk and/or Echolink systems.

History

The IRLP system was introduced in the late 1990's as a way to connect remote repeaters using the Internet, rather than telephone lines or RF links.

Since that time, VOIP radio technology has progressed quite rapidly. Several other VOIP systems have come and gone, each with different features and capabilities.

Systems such as Echolink and Allstar have surpassed IRLP on every level.

For example, IRLP can only support half-duplex audio, and requires an expensive proprietary interface. The IRLP software is closed source, and not compatible with other networks such as Allstar.

Echolink and Allstar are both free. Allstar is open source, and Echolink is friendly to other software developers, allowing add-ons to coexist with the Echolink software.

Required Equipment

Converting from IRLP to Allstar or Allstar and Echolink is quite easy. The Allstar app_rpt software directly supports the parallel port, so your existing IRLP board can still be used for PTT and COS.

The Aux 1,2,3 outputs are also supported.

The only additional item you'll need is a CM108 or CM119 USB Sound Fob. Click on the picture for more information and pricing. For reference, I ordered StarTech.com model# N82E16829128004

Allstar is capable of much better audio quality than IRLP. Because of this, Allstar does not support analog sound cards such as Sound Blaster, on-motherboard sound cards, etc.

The C-Media CM108 or CM119 USB Sound fob is capable of much higher quality audio than an analog sound card.

Because you will be using your IRLP board for PTT and COS, you will not need to modify the CM108 or CM119 for PTT and COS! This makes converting from IRLP to Allstar very easy.

The easiest way to get started with Allstar is to download the ISO on the Allstar web site, and burn an Installation CD .

NOTE: The installer will repartition your hard drive and install CentOS 5.1 (Linux) and Asterisk. The installer does not ask which hard drive to install CentOS to (Most Linux Installs will!), and the software will be installed to the first hard drive. I lost a Windows XP drive this way!

Here is the node definition in usbradio.conf from my IRLP-board driven Allstar node.

Note that if you are handling the PL encode and decode in the radio (not in Asterisk DSP), you can use SimpleUSB instead of Usbradio. There is no down side to SimpleUSB if you handle the PL in the radio (as I do!)

The benefits are, less CPU and memory usage, the ability to run multiple nodes on a minimal PC, and less audio "jitter" than with Usbradio.

[usb1234]
 
; IRLP board support
pp3 =  ptt       ; out0, out1 or ptt
pp11 = cor
;
pp4 = out0      ; pins 4,5,6 are AUX 1,2,3, default off
pp5 = out0
pp6 = out0
 
hdwtype=0
rxboost=0
txboost=0
rxctcssrelax=1
txctcssdefault=100.0          ; Disregard this CTCSS section unless you are using discriminator
rxctcssfreqs=100.0            ; audio and injecting PL from the USB FOB directly into the modulator.
txctcssfreqs=100.0
;rxctcssoverride=0            ; If using a typical IRLP setup - muted, filtered receive audio and injecting mic audio 
                              ; into the mic jack, you'll want to do your PL encode and decode
;carrierfrom=dsp              ; in the node radio itself, not via Asterisk DSP.
ctcssfrom=no
carrierfrom=ppinvert          ; use either pp or ppinvert
;carrierfrom=pp               ; depending on the cos logic of your radio
rxdemod=speaker
txprelim=no
txlimonly=no
txtoctype=no
txmixa=voice
txmixb=no
invertptt=0
duplex=0                      ; 0=half duplex    1=full duplex
rxondelay=0
rxnoisefiltype=0
eeprom=0