OT: adding RS232 to new computer

newguy · Joined: 24 Jun 2004 Posts: 1911

Does anyone have some recommendations for adding 1 or 2 serial ports to a new computer that didn't come with any?

I'm looking for the standard 9 pin serial ports. I'm strongly leaning to a PCI card solution as I'm not sure how good the USB<->serial cables are. Recommendations and/or anecdotes concerning either solution would be welcome.

My very reliable but old computer's main drive packed it in over the weekend and I decided to get a brand new computer instead of trying to wring more life out of the old one.

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

I've used the Siig brand and it worked OK. They have several PCI
cards with two DB-9 serial ports:
http://www.siig.com/productlist.asp?catid=98

cmdrdan · Joined: 08 Apr 2005 Posts: 25 Location: Washington

Newguy --

I had a similar experience about a month ago! I bought one of the USB-DB9 serial converters, but had problems getting it to work with all of my devices. I decided to try a two-port PCMCIA card from Quatech and those problems have been resolved. I was toying in my mind between a one-port and a two-port card, and the two-port card wasn't that much more money....

Hope this helps

Dan

Neutone · Joined: 08 Sep 2003 Posts: 839 Location: Houston

I suggest reading this app note for USB to serial chips made by FTDI. It gives a clear understanding of whats going on with a USB serial port and why specific applications don't work over a USB to serial converter.
http://www.ftdichip.com/Documents/AppNotes/AN232B-04_DataLatencyFlow.pdf
Understanding the limitations you can write your own software to work around them.

ckielstra · Joined: 18 Mar 2004 Posts: 3680 Location: The Netherlands

We have good experiences with the Moxa PCI cards. Not cheap, but good driver support.

newguy · Joined: 24 Jun 2004 Posts: 1911

Thank you to everyone for the information. I ordered a PCI card-based solution.

This whole experience has taught me the importance of backing up my work regularly. Most of it was backed up, but unfortunately not all. Through nothing but blind luck, I was able to read the non-backed up data off of the old drive before it did finally pack it in permanently. Dodged a big bullet there.....