Compatible PCI Serial Cards & USB to Serial Adapters

[shpegel]

I need to test RS-422 and RS-485 devices and BIT's serial port loopback test is excellent for this as long as I use the serial port on my desktop computer. Laptops with USB to serial and PCMCIA serial ports all have various issues that look like timing problems with the drivers.

I would like to know what type of add on desktop PCI serial port cards BIT users have had success with. I have purchased a B&B 4 port RS-422/485 card and but BIT does not work correctly with it. It appears to be timing issues as it insistes there are framing errors even when looking at just the loopback plug.

Alternately if I use a desktop Com port with a external RS-422/485 converter, it works perfectly. The problem is I need to test quite a few ports and having additional serial ports would really speed things up.

For those who know RS-485: I test two RS-485 ports back to back with my B&B RS-485 convertor in 4-wire RS-485 mode connected to my desktop com port. It works great but I need to test 3 other sets of ports at the same time.

Also, I need to do this from my laptop when in the field and the Quatech 4 port PCMCIA card I am using also has it own set of issues with BIT (framing errors and refuses to ignore control lines). Even my IOgear USB to Serial adapter refuse to allow BIT to set baud rates above 56KB although it works pretty well at the lower speeds.

Anyone had luck with a USB to serial adapter especially at high speeds?

I would be happy to share my test wiring diagrams with any who are interested.


Many Thanks,

Howard

[David (PassMark)]

We have not done any testing with 422/485 devices ourselves, but there is no reason why they shouldn't work with the serial port test.

We did do some testing with multi-port RS232 cards and we are not aware of any incompatibilities.

If you are seeing framing errors, did you try to set the "Use RTS/CTS" flow control option in BurnInTest?

As for the IOgear USB to Serial adapter not working at speeds above 56KB, you should contact IOgear as according to their web site, their device supports over 230Kbps (RS232).

[shpegel]

Thank you for the response.

We have not done any testing with 422/485 devices ourselves, but there is no reason why they shouldn't work with the serial port test.

Actually 2 wire RS-485 does provide a challenge to doing loopback testing as it is half-duplex. However the device I test has 2 RS-485 ports and the B&B converter used can do 4 wire RS-485. This makes it possible to test both ports at once in a single direction by looping them together at the far end.

We did do some testing with multi-port RS232 cards and we are not aware of any incompatibilities.

This is good to know. I am going to order a couple to try. Any reccomendations?

If you are seeing framing errors, did you try to set the "Use RTS/CTS" flow control option in BurnInTest?

I thought I had set them correctly but recently I noticed I had misread the second check box item and this could be the issue. I will retest and let you know.

As for the IOgear USB to Serial adapter not working at speeds above 56KB, you should contact IOgear as according to their web site, their device supports over 230Kbps (RS232).

I'll give it a try but I have successfully used the adapter at higher speeds for other applications with no problem albeit just communication utilities. It has been my experience that the results of USB to serial adapters will vary quite a bit with computer used and driver version. Again, any reccomendations would be helpful.

Many thanks.

[David (PassMark)]

The last multi-port testing we did was with the Digiboard Accelept 8r 920-PCI Adapter (8 port RS232).