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).
Click on pictures to enlarge image.
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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In October 2010, I suggested parallel port functions be added to the Asterisk (Allstar) software for PTT/COS/AUX. Jim (WB6NIL) was very accommodating,
and quickly added this functionality to app_rpt (Allstar). This approach consists of using an unmodified
CM108 USB fob
for audio, and a parallel port interface
such as the PLRI (or IRLP) for connection to the radios.
I quickly realized that Asterisk could easily support up to 5 simplex radios, or 5 duplex repeaters, and 3 aux outputs from a single parallel port!
NOTE: You can scale this design as needed to support from 1 to 5 radios/repeaters.
Besides the parallel port, two DB9 serial connectors are provided. These ports can be connected to a PC serial port, USB/serial adapter, or just used
as additional inputs / output ports.
The audio section is identical to my homebrew
Rigblaster-type interface, and is built 5 times on a single PCB.
The logic section uses 3 ULN2803 ICs, and 4 MPQ2907 ICs. The ULN2803 has 8 Darlington NPN transistors in an 18 pin IC (50v, 500 mA per switch),
and the MPQ2907 has 4 PNP transistors in a 14 pin IC(60v, 600mA per switch).
The total number of transistor switches is 40. The ICs are socketed, making replacement much easier than with discrete transistors.
I have configured 1 ULN2803 and 1 MPQ2907 for 12v (RS232 logic), and 2 ULN2803 and 3 MPQ2907 for 5v (Parallel Port/TTL logic).
This interface is compatible with Allstar / app_rpt, Echolink, TheLinkBox, IRLP, RptDir, TheBridge, as well as any sound card digital mode, such as PSK31,
voice keyer, SSTV, etc.
As with the other PLRI designs, great care is given to maximum flexibility. Positive or negative PTT and COS are supported, and active low or active high
auxillary outputs are also supported.
LEDs are provided for COS, PTT, AUX, and Power.
Two header pin connections are provided for each transistor switch pin, so that you can connect inputs, outputs, and LEDs as needed. An example would be a radio
PTT using a parallel port pin. Connect the parallel port pin to an NPN input, then connect the NPN output to a PNP input and your radio's PTT line. The PNP output
(active high) connects to your PTT LED.
NOTE: This list is not yet complete.
Jameco parts list
-----------------
1 qty p/n 2117106 10 7" female jumpers $6.95
1 qty p/n 149623 26 pin cable $3.95
2 qty p/n 1952265 9 pin cable $1.49
1 qty p/n 496296 26 pin connector $1.79
1 qty p/n 67812 9 pin connector $.59
1 qty p/n 51262 7805 5v regulator $.25
1 qty p/n 51334 7812 12v regulator $.25
1 qty (per radio) p/n 125357 Audio transformer 1:1 $3.49
3 qty p/n 26454 MPQ2907 IC $1.25
2 qty p/n 34315 ULN2803 IC $.59
10 qty p/n 23077 LED mounting $.15
5 qty p/n 333973 Red LED (PTT) $.12
5 qty p/n 34825 Yellow LED (COS) $.15
1 qty p/n 34761 Green LED (Power) $.15
1 qty p/n 152785 Red LED (AUX) $.12
1 qty p/n 333201 Green LED (AUX) $.15
2 qty p/n 34657 Yellow LED (AUX) $.12
1 qty p/n 1849591 (bag of 100) 10k resistor $2.95
3 qty p/n 117197 Header Male 80 Position 2.54mm $1.25
2 qty p/n 2095437 (per radio) 3.5mm stereo jack $1.49
Radio Shack parts list
----------------------
1 qty p/n 270-1809 Project Enclosure 8x6x3" $8.99
1 qty p/n 276-147 General Purpose PCB 6.13" x 4.5" $4.49
1 qty p/n 276-0079 Panel Mount LED holders (5 qty) $1.99
1 qty (per radio) 273-1380 Audio transformer CT $2.99
1 qty (per radio) 273-1374 Audio transformer 1:1 (discontinued?)
5 Radio serial / parallel interface (logic PCB)
5 Radio serial / parallel interface (rear panel)
5 Radio serial / parallel interface (audio PCB)
Asterisk parallel port interface
Features include:
No expensive USB fob from overseas needed, just a generic, unmodified
CM108 USB fob
This circuit can be used with:
All Star Link (Asterisk)
Users can operate any VOIP mode supported by the software, including IRLP, Echolink, Asterisk, etc.
This interface can be connected directly to the node radio(s), or used with a
Rigblaster-type interface.
The plastic enclosure was used at my QTH, while the metal one was built for my repeater site. The circuits inside are
identical.
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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MT8870 Availability
I am often asked if the MT8870 DTMF decoder IC is still available. They are readily available in
SOIC packages. If you prefer a DIP package (as I do), I suggest searching Ebay for MT8870.
Deluxe PLRI interface
This is my deluxe PLRI interface, which has every feature and capability
of the IRLP v3 board, including:
Build it yourself for $20 or less!
EchoIRLP
TheLinkBox
RtpDir
Here are a couple of prototype PLRI interfaces that I built. These are constucted in an enclosure, not designed to mount
inside a PC. I prefer to have the interface near the radio(s) where I can easily observe the status LEDs, and easily
connect to the AUX ports.
PLRI Aux 1,2,3 retrofit
This circuit allows those without V3 boards to utilize the three Auxiliary outputs found on the IRLP
Version 3 board.
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