What's the best method for an internal PC connection?


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I knew about this before I purchased the LCD screen from CrystalFontz, but I thought, "Oh I'll just worry about that when it gets here."

Well, now my case is open with the included serial cable ran to the back of my PC's serial port. The only other way I can think of to get this hooked up internally would be to solder wires to the back of the motherboard. Which means I'd have to pull everything out.

In the previous post I saw there were only 2 wires that need to be hooked up to the serial part of the panel. Is this true in my case?

A paper that came with my display mentions "Most RS-232 ports will be able to power the display through their DTR and RTS lines. Just have the software drive these lines high-- most software already will." From this I concluded I'd need those two as well. But this seems not to be the case? Please help! :)

I do wish there was a simpler way of getting an internal connection for a PC, but noone can really be blamed for that. I would however suggest a cable option for an easier internal connection. What I will probably do is buy an internal 9 pin DB connector connected to a nice long ribbon cable, and strip and cut the wires I don't need. This should make for a clean-looking harness. After all, this is what case modding is all about.

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CF Tech


Back in the good old days of the "AT" style motherboard, there was often a 2x5 header on the motherboard that would have a short cable to a connector for the COM port. These were great since a simple ribbon cable could be used to bring that COM port to the display and the whole thing would stay inside the case.

Then the ATX came along with its outlandish notion that all RS-232 connections would be to devices _outside_ the case. Nothing but trouble for the LCD folks. Well, there are a couple of solutions, although none of them are particularly wonderful.

1) Add a 2-serial, 1-parallel PCI or ISA card to your system.

You always wanted another parallel port, right? The 2-serial, 1-parallel cards typically have the parallel 25-pin connector and the first serial 9-pin connector mounted directly to the card, with the second serial connector on a short cable hooked to a 2x5 header--just like the good old days! Here is a PCI card from ByteRunner that I have used:


The same card is available from CompUSA:


Last time I checked, both of these cards are really from Startech, but they do not do end-user sales:

http://www.startech.com/parts/iocards.htm frame, so select "Combo I/O Cards" then "PCI2S1P" to get to here:

I would stay away from ISA cards, since there is no good way to get around the I/O address and IRQ problems with them, and this usually means disabling one of the COM ports on the motherboard. Here are the parts to order from Digi-Key (1-800-344-4539) to make the internal cable:

C1AXG-1036G-ND (6' cable with one 2x5 connector attached):
CFM09G-ND (extra connector that you can put where you want):

I think the cable ends up having some wires crossed to make it work with these cards:

2) Hook the display to the USB (really:)).

Aten makes a nice cable that will add a COM port to your computer through the USB:


It is available here:


You would then hook it to the spare USB connectors that are usually routed to the back panel. In the spirit of case-modding, you might be able to remove the USB end of the cable and connect that directly to the spare USB header on your motherboard. You would want to make sure that the USB cable connector does not have any electronics in it, the serial end certainly does have electronics in it, so don't hack that end.

3) Use our standard standard serial cable (WR232Y01), but use a Dremel to notch one of the slot covers to let it out of the case:

4) Make your own ribbon cable with two "IDC" DB-9 connectors. This still needs to exit the case, but at least the flat cable is easier to pass through a small hole to the outside of the case. Here are the parts to order from Digi-Key (1-800-344-4539):

C7FXG-0906-ND (6' cable with one DB-9 attached):
CFM09G-ND (extra connector that you can put where you want):

5) As you suggest in your post, you could wire up the display directly to the back of your motherboard, carefully soldering to the correct pins of the motherboard's DB-9 from the back side. If you connect the backlight power cable (WR232Y02) to both LED+ (where it goes by default) and also to VCC on the display (this can be done with a solder bridge on the back of the display's J2 connector), then the display will only need the RS-232 data and ground from the PC's serial port. It is basically the same idea as this post, just compressed to being totally inside the case:


However, I am not sure how excited I would be to take a soldering iron to my new KT7A . . .

Well, hopefully one of these methods will work out OK for you.
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New member
What an incredible reply! It was so thorough and well planned out, it's almost like you have the answers ready in anticipation for the questions. :)

From your ideas I figured out a simple, but elegant solution. I just wish I could take pictures for you.

I took your #3 suggestion and used your standard serial cable, but modified the way I hooked it up. The connector on the cable wouldn't fit through my card slots in the rear of my case, or I would have just done that temporarily.

Most cases nowadays also have extra holes in the back of the cases for things like extra 9 and 25 PIN DB connectors. Because they're covered by the factory with a perforated plate, I totally forgot about them until I read your reply.

What I did was take the supplied standard cable and put it on the inside so you could see the connector on the back. I popped out the plate and took 2 nuts that fit the threads on the end of the connector (your 9-pin DB) perfectly, then secured it to the back of the case. Then I hooked up a second external standard Male-Female 9-pin serial cable between the supplied cable and my external serial port. At the moment it's a fairly long cable, because that's all I have at home. But at least I can now close up my case. If you were to use metal motherboard stand-offs instead of screws, you'd then be able to screw in your external cable into the stand-offs. I will probably purchase a very short 4" cable to remove the slack.

What this gives you is a more elegant way to transport your case, if you need to, so you won't have a cable dangling out of the case.

Again, I do wish I had pictures. I really need to buy one of those digital cameras. Yours looks nice, which one is it?

Thanks again!

CF Tech

I am glad you found a solution you like!

The digital camera is a Sony DSC-S50. Great camera, but get a 64MB stick, the standard 4MB stick does not go very far.

We are pretty excited about the new forum. I don't know how many times we have answered this question in individual e-mails, it is nice to spend the time to compose a comprehensive answer and know that we can refer to this thread if someone has a similar question.


New member
Just curious Brent... Cypress offers a chip in their EnCORE line of USB controllers that is essentially a complete USB-on-a-chip setup, with EPROM and an RC oscilliator onboard, 11 data lines - just enough to control a 44780 LCD. I was thinking of experimenting with it as a directly USB connected LCD, but the cost of a USBID makes it prohibitive for hobbyists :) Any intentions in this area?

CF Tech


Thanks for your post.

I think the time for USB is certainly drawing near. As it always seems, the hardware is pretty easy to knock out, then the software drags on and on. The Cypress part would certainly work for an LCD.

I think for experimenting, you can get away with using the part's default Cypress ID--talking to it with the demo Cypress software kit. You only need the real ID if you want to ship it to customers that picky enough to not want it to say "Cypress" when you plug it in.

I think one of Cypress's parts is RAM based and comes with just enough ROM to be recognized by the system. The system then gets the application code from the driver and sends it down to the part. The ultimate firmware updating system -- new firmware every time it boots.

I think to make use of the USB bandwidth, it would be most useful to put USB on a graphic display.

Keep watching . . .

CF Tech

You just need to make the connections as detailed by the backpack manufacturer. You can use an IDC connector on a ribbon cable with a 2x5 0.1" center header. Solder the wires directly to the backpack, whatever you would like.
USB LCD Displays - Graphic and Character LCDs with a Keypad


New member
by the way thanks for helping me :) a person said that the verson of Lcdriver out now does not support parellerl Lcd's does that mean the same with the serial backpacks? I would think not......

CF Tech

I think LCDriver may support a couple of the backpacks. I would check the site first to make sure the one you get is supported.


New member
crystalfontz said:
I think the time for USB is certainly drawing near. As it always seems, the hardware is pretty easy to knock out, then the software drags on and on.
think to make use of the USB bandwidth, it would be most useful to put USB on a graphic display.
Keep watching . . .
I know this is an old thread but... If I could make a suggestion to Crystalfontz -- If you start offering a USB version of any LCDs, may I suggest having two cabling options available? One actual USB connector, and one that is a USB Header connection? My motherboard has a total of 6 USB ports (2 on the back and 4 through USB headers that you plug in to). Granted, I'm not sure if there's a "standard" for USB headers, but I have a lian-li case with built-in USB ports and the way they got around that was simply labeling the lines USB-, USB+, GND, and +5V. Using a USB header connection would keep the wires nice and hidden within the case :)

edit: Also, those links to the digikey parts are broken and I did a search for the part numbers but came up with nothing. Odd.
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New member
As for teh comment about the standard of USB headers... There apparently isn't. I have a KG7-RAID mobo and a CoolerMaster201SX case. The wiring on the Coolermaster USB port cable uses all 5 pins for each USB connector, while the KG7RAID rear port USB uses two wires on the first pin, and has removed the last pin on the mobo as a "guide" pin.

Also, I'd just reccomend everyone order the catalog. It makes life easier when you're a n00b looking for stuff like me :D


New member
Here is another way to neatly connect your LCD. I have used a pre-punched backplate (see pic, you might be able to take one off an old video card?) and a "port saver" i.e. a m/m DB9 connector. Then you can connect two serial cables, one in side the case and a shorter one outside.




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New Motherboard

I am one of those people with more money than sense. I just bought a ABIT IT7 motherboard. One of the key features of this board is that is legacy free (i.e. no serial or parallel ports). It has every thing else though ( 6 USB 2.0 and 2 IEEE1394 firewire ports). Is there a way of directly conneting to the motherboard or through one of the USB ports. I haven't purchased yet but I would like to if there is a clean way to hook up the LCD display

CF Tech


We now are shipping PDBK* bracket kits are with the WR232Y09:

and the WR232Y10:

This makes a clean solution for connecting the internal serial LCD to the external serial port:

They will be available separately soon.


New member

crystalfontz said:
Crystalfontz now has USB-RS232 converter cables that will allow you to run your serial display (or any other serial device) from your USB port:


There are complete solutions for only $29.00
That's great, I'm glad to see USB finally making its way in. Has anyone found an internal USB cable? Most motherboards have a couple of internal USB headers, so why couldn't I use that?

Would it be as simple as making my own end? If so, does anyone know where I can get a pinout chart?