NOTICE:
In response to a "cease and desist" email by Dave Cameron (Creator of IRLP), I will no longer refer to the circuits
shown here as IRLP circuits. IRLP is a registered trademark of the Internet Radio Linking Project, and/or Dave Cameron.
While my circuits are fully compatible with IRLP, these circuits are of my own design, and therefore
not reverse-engineered versions of the IRLP board. To avoid confusion, my circuits will
hereafter be known as PLRI (Parallel Logic Radio Interface).
This page has information on my PLRI circuits. See the
left side of the page for other operating modes and projects.
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This circuit can be used with:
EchoIRLP
Users can operate any VOIP mode supported by the software, including Echolink, Asterisk, DStar, etc.
This interface can be connected directly to the node radio(s), or used with a
Rigblaster-type interface.
TheLinkBox
All Star Link (Asterisk)
RtpDir
PLRI Aux 1,2,3 retrofit
Note that this circuit as built will handle one auxiliary output. I like to build this circuit on a small PCB and mount it inside a PVC type outlet box.
This is a simple transistor switch configured as a relay driver. In the circuit shown here, the TTL signal from the parallel port causes the transistor to provide a ground signal to our relay.
By using a SPDT relay, we have the option of using both the normally-open (N.O) and normally-closed (N.C) contacts for our auxiliary circuit. For example, I like to use the normally-closed contacts for transmitter control. In this setup, the relay coil remains de-energized most of the time. The only time the relay is energized is when you want to remotely shut off the transmitter.
In this circuit, AC outlets are used to allow typical 120v AC circuits to be controlled, but the circuit is easily adaptable to other needs or requirements. For example, if you'd prefer to switch DC circuits instead, you can substitute a relay rated for your needs.
The 2N3904 transistor is rated for continuous collector current of 100 mA, so make sure that the coil current requirement of your relay is well below 100 mA.
I've found that controlling 120v AC outlets is the ultimate in remote control. Besides switching 120v AC loads, you can connect a 120v AC relay to one of the outlets shown in this circuit. This would provide the user a set of isolated contacts. The sky's the limit here. Connect your garage door opener, doorbell, whatever.
You can also use this isolated set of contacts to switch DC, if desired, up to the rating of the relays.
Keep in mind that the total current draw across the Radio Shack #275-248 relay must not exceed 10A at 120v AC in any
situation.
Using a DB-25 type computer data switch, connect the common port to your IRLP board. Connect one other port
to the PC parallel port, and the last port to this circuit. Now you can switch between IRLP operation, and
serial port digital modes easily.
This circuit is also compatible with Echolink and most other digital modes, including PSK31.
Another benefit to this circuit is that you can isolate computer problems by using
a PC running a different operating system (such as Windows). I don't know of any other
adapter to allow using an IRLP board outside of Linux.
While I recommend using the deluxe interface shown above, this was the original "proof of concept"
circuit and does work.
All features of the IRLP V3 board are supported by this circuit, including DTMF decoding, COS, PTT, etc. Aux 1,2,3
were supported by using external transistor relay drivers (shown separately).
This interface can be used with the same software as the Deluxe interface.
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PLRI board adapter
This circuit is helpful if you want to use your IRLP node radio for other digital modes, and are looking
for a simple way to switch back and forth. For example, you run a simplex node on IRLP, but occasionally
want to participate in a SSTV net, or operate PSK31. Such software typically requires a serial port interface.
Basic PLRI interface
This is a simple circuit that allows you to connect a standard
Rigblaster-type interface
to the IRLP computer for testing purposes.
Thank you for visiting my site, I hope that it has been helpful for you. Don't hesitate to
email me
if you need help with your ham station, or to set up a sked! 73, Kyle