MS Access/Serial to USB Connection Error

The runtime error 8018 its a communication error that means that you are triying to perform an operation that is valid only with the port open, check your old VB program and check when you open the serial port and when you close it, maybe you are closing it when you need it to be open.

Sometimes it is best to bring the old serial port back again with a card.

http://www.lavacomputers.com/index.php?id=762

i agree with that answer too jeje

Unfortunately, none of the cards I saw on your link were for laptops. Are there any? I basically don't use desktops any more. What I need is effectively to add an old RS232 9-pin port to a laptop. What I would really prefer would be to add same to my Mac laptop. My PC laptop would be second choice, and any non-portable would be a distant third choice. I have had very poor luck with USB to Serial converters.

If you need to brew your own converter, these people offer one of the easiest solutions I have found. They also provide drivers to manifest the part as a serial port in Windows. http://www.ftdichip.com/

Eliminating the serial port on laptops prematurely is one of the stupider things they have done, and it has caused many problems for tech people. As to PCs, if you need a serial port, don't buy a computer without one ... its that simple.

I know a number of companies keeping old computers around, running Windows 98 solely to maintain the necessary ability to run older software and interface with older equipment.

Its funny to me how in the early days, getting serial devices to talk to each other often required us to use a suitcase sized serial analyzer to see what was going on so we could correct it. Then, the PC standard spread across all office equipment and eventually most industrial equipment and things became simple.

Now, we seem to have taken a few steps back. All USB to serial converters are not created equal, and some work in some applications, and others don't, with no way to tell ahead of time which one will work for your specific application unless you know someone who has used it. They almost all work fine with relatively recent standard office equipment, but its the "other" stuff that gives them problems.

The problem my well lie in your VB program related to a timing or buffering issue when its running on XP over the USB port.

For PCs you can add a PCI serial card.

A solution for laptops is to add a serial port via the PCMCIA slot. There are a number of suppliers of these cards on the web.

Some links:

http://www.usbgear.com/1x-Serial-PCMCIA.html

http://www.nextag.com/pcmcia-serial-port-card/search-html

Greg

Greg

Thanks for the links! I'll do some more research to decide which to try.

Anybody out there had success connecting a recent (no serial port) Mac to PLCs or an old ScanTron Mark sense reader?

Dick

We successfully used the FTDI parts noted in my above post to interface instrumentation to a MAC via USB. FTDI also provides drivers for the MAC operating system.

Thanks rcapper.

Are the FTDI parts chips you use to make your own interface board? I'm quite willing and able to do that, as long as there are no more than two layers of copper and the traces don't have to be too closely spaced.

I have sent an email to FTDI...

Dick

Yes. There is also a company, I think it is DMI that makes small modules already assembled with a flash Microchip microcontroller that you can program. The whole affair will plug onto an IC pattern on another board our you can wire directly to it. If you can't find DMI let me know and I will dig up what I have on them for you.

I found a reference to DMI Partners, Inc., but it led nowhere...

Thanks again.

Dick

Sorry, about all I got right is it starts with a "D" and has three letters. Here is the link: http://www.dlpdesign.com/

Thanks-that link worked. I'm still not sure whether that is the way for me to go.

Over the last 25 years, I have developed a program, currently in Real BASIC, that connects a Macintosh computer to a ScanTron optical mark sense reader via RS232 to grade tests and analyze the results for the Academic Decathlon (so the program is used only once a year). Unfortunately, I have not succeeded in making the program connect the scanner with the newer Macs that have no serial port. I have tried to use USB-Serial converters, with no luck. I only need to send a 3 character command to initiate reading, then accumulate the returned string. I do design my own logic circuits (mostly CMOS), make my own circuit boards, and am quite familiar with several RS232 pinouts and cables. I am also interested in connecting a Mac Powerbook or MacBook Pro to Galil Motion controllers, but that is a lower priority, since it can be done via ethernet. Thank you for any assistance.

You might want to look at the Circuit Cellar website. I believe they ran an article recently on a small circuit that converted ethernet to RS232.

You just opened a whole new can of worms!

I'm currently programming in REAL BASIC, version 4, which is now 5 years old (I thought it was only a couple of years old - how time flies!). I just ordered the 2007 version upgrade. When it arrives, I'll find out if and how it may be able to communicate to an old RS232 device via USB, Ethernet, IR, Bluetooth, etc. from a Mac using OS10.4. Or maybe I can just get a new Mark-Sense reader that connects via USB...

Thanks one more time! Dick

The com port on Dos and Windows (up to 98) could be accessed in 232 ways. To achieve speed and to work around errors in communication chips programmers improvised a bit and wrote to the ports directly and other tricks. Your problem may be that XP do allow for these tricks because it does not fit in with modern requirements.

Procedure to access ports directly in is however available for downloads.

Hendrik,

Good point!

There is likely some of that going on here involving the VB serial port code with either XP and/or the USB to RS-232 converter.

Do you have a link to this downloadable procedure?

Greg

A Magma box uses a PCMCIA card (not all Laptops have such a Port today!) to produce an extended 32 or 64 bit PCI expansion frame. There you might be able to plug a serial card in provided it is PCI!

This is a large hammer to crack a very small nut as the 32 bit box costs around $700 if my memory serves me correctly (check on the internet for the facts!)

Personal experience showed me that the when compared to each other, the 64 bit boxes are actually slower than the 32 bit boxes! even when using the same 64 bit PCI card in either box.....it would appear that the conversion was not quite kosher.

We found this out a couple of years ago and I returned the 64 bit box and they gave me my money back. They could not fix the problem though they wrote several new codes for the box!!

The support people were really nice and friendly and did their level best to help. I personally feel that the problem was a poorly designed hardware, but this was never proved, though the electronics appeared to be almost identical to the 32 bit box......

The 32 bit boxes though are just great.....solid and reliable, I never saw one go wrong and we went all over the world with hundreds of these boxes in my time!!!

Hi......

the same prob. i had face in my early days of project...

actually i think you wanna go for communication between PC and the external device....

use RS-232 for communication .....

map your VB program with your external device program ...and make a connection between RS-232 and USB....

if any other query with this installation you can ask me........

The weak link for me is your paragraph connecting USB to serial.

Over the last 25 years, I have developed a program, currently in Real BASIC, that connects a Macintosh computer to a ScanTron optical mark sense reader via RS232 to grade tests and analyze the results. Unfortunately, I have not succeeded in making the program connect the scanner with the newer Macs that have no serial port. I have tried to use USB-Serial converters, with no luck. I only need to send a 3 character command to initiate reading, then accumulate the returned string. I do design my own logic circuits (mostly CMOS), make my own circuit boards, and am quite familiar with several RS232 pinouts and cables. I am also interested in connecting a Mac Powerbook or MacBook Pro to Galil Motion controllers, but that is a lower priority, since it can be done via ethernet. Thank you for any assistance.

I had the same problem when both of my ThinkPads died/ running Windows 98. I abandoned laptops all together and have gone to a handheld, which I use with raw IR to download equipment through an IR to serial adapter. Works well...But I have to move the data to a desktop to really study it. Also, switching to Widnows XP on one of my desktops, and to a newer version of Excel rendered a VB application I wrote for Excel 97 unreliable. Microsoft has no idea why it works for some equipment, and not others...The greatest advantage for me with the handheld, though is weight savings/ most of my work involves travel to remote sites, and losing 20 pounds of baggage has really saved me money!

Charlie