ChrisAlley.com

Turn a HP C4103A IrDA / FIR adapter into a standard PC IrDA module (For motherboards with IrDA on-board). How to convert your HP C4103A into a usable SIR, MIR and/or FIR PC Interface. Simple modification instructions… assuming you know how to use a soldering iron, and have a basic understanding of electrical components.

HP C4103A IrDA/FIR Adapter

If you have a motherboard with built in IrDA, but no Ir module then this may solve your problem for free. These IrDA adapters from HP came with every laserjet 4050 we bought recently, so we had about 10 or so to experiment on. They don’t send them with the printers anymore, you have to send off the request card in the box to get one, they used to be free, but I’m not so sure anymore. So far, it has worked great to sync my Nokia 3360 phone and my Jornada Pocket PC (which is better than its career as a printer adapter… I never got it to work).

Even though the HP plug looks kinda like the one on the Asus connector, DON’T TRY TO CRAM IT IN THERE, it will blow a fuse, if not make something smoke!!! You might as well cut the plug off now, as it is of no use.

I have the cord running in through an open expansion slot, and connecting straight to the motherboard. You will need to find the pin out of the IrDA connector for your motherboard, for reference I will use the asus connector block (most will be very similar) To find your pin-out of your motherboard check the website of its manufacturer.

The reason we need to modify the HP adapter is that it uses a differential Tx signal ( Tx+ and Tx- )…
For IrDA both signals are just 1 wire each (ignore the FIR-RxD)

For a better explanation see the pages by Ralf Probst & Andreas Schüßler

Here it is in 5 easy steps:

1. Remove Screws – First punch 2 holes in the label on the bottom with a pushpin or small screwdriver…*Some have 4 screws, Check the round little rubber feet for more.
2. Attach a Jumper – Find a 1.5 inch scrap of wire (I use one of the wires from the LED). Solder your scrap to RX1 closest to the IR module (if you follow this trace it goes to pin 7 of the IR module, but its easier to attach it here if your not very good with a soldering iron). ** leaving the LED may cause problems, so go ahead and clip both wires at the board… unless you want to do some testing on it for me.
3. Remove pink wire – from connector block and strip it enough to solder or twist on the other end of your scrap… (see finished images 1 2)
4. cut off original connector…you can use a CDaudio patch cable with its 4 block connector (cut the patch cable in two, and splice the Tx/GND/Rx in to one half… cut all but one wire out of the other and splice it to the +V)…you can use a paperclip or knife to pry up the plastic clip and remove the crimped connector…
5. Reassemble and Enjoy – I’ve had several people ask me how to install drivers for IrDA ports. But, I’ve had no trouble with my ASUS board… once I enable the IrDA function in the bios Windows (98, 2K & XP) finds the device and installs default drivers without any help from me.

2) Attach a Jumper - Find a 1.5 inch scrap of wire (I use one of the wires from the LEDsolder your scrap to RX1 closest to the IR module (if you follow this trace it goes to pin 7 of the IR module, but its easier to attach it here if your not very good with a soldering iron) ** leaving the LED may cause problems, so go ahead and clip both wires at the board... unless you want to do some testing on it for me...
Step 3	3) Remove pink wire from connector block and strip it enough to solder or twist on the other end of your scrap… (see finished images 1 2)
Step 4	4) cut off original connector…you can use a CDaudio patch cable with its 4 block connector (cut the patch cable in two, and splice the Tx/GND/Rx in to one half… cut all but one wire out of the other and splice it to the +V)… you can use a paperclip or knife to pry up the plastic clip and remove the crimped connector… ASUS IrDA Header 5v Purple no connection Rx Teal (green?) GND Yellow Tx Pink
Step 5	5) Reassemble and EnjoyI’ve had several people ask me how to install drivers for IrDA ports… but… I’ve had no trouble with my ASUS board, once I enable the IrDA function in the bios Windows (98, 2K & XP) finds the device and installs default drivers without any help from me…

Email me with questions or comments IrProject@chrisalley.com

Please feel free to link to this site!

Credits:

Special thanks to Ralf Probst & Andreas Schüßler who did all the hard work and research here, check out their work:
Schüßler Asus TX97-E Infrarotprojekt von Andreas Schüßler translate with google
Probst: HP-IrDA C4103A an Asus Mainboards Infrarotprojekt translate with google

Dschen Reinecke’s Infraredport-page! ( www.infraredport.com for English / www.infrarotport.de for German )

I found that translating technical instructions from German is very difficult (and some errors are quite funny) that’s why I’m doing an English page. I thank all of you who have emailed me with questions and praise… Your questions keep me thinking about this project and updating it when ideas and problems pop up. Please let me know if you got it working and how you did it.

Other Languages: (these sites have links to this page)

Hebrew: HWzone (looks like a message board, I have no idea what it says)
http://www.hwzone.co.il/community/index.php?board=1;action=display;threadid=14647;start=0

Email me with other C4103A sites or boards and I’ll add them here.