We help IT Professionals succeed at work.

We've partnered with Certified Experts, Carl Webster and Richard Faulkner, to bring you two Citrix podcasts. Learn about 2020 trends and get answers to your biggest Citrix questions!Listen Now


Cannot change Com3 settings at command prompt

HouseofFara asked
Medium Priority
Last Modified: 2010-04-26
System is XP Pro.
PC has (4) com ports.  1 & 2 are the standard integrated on mother board.
3 & 4 are via a PCI communications add in board.

Windows recognizes all 4 ports fine and I can change settings accordingly.

However, I have  (4) barcode printers that use the command prompt
PRINT function.  I can change Com ports 1 & 2 via the MODE command
at the C:> but cannot change ports 3 & 4.

When I issue the following:

mode com3: baud=9600 parity=e data=7 stop=1 xon=on

the response is displayed as:
com3   baud=1200

Again, I can change ports 1 & 2 fine, but not 3 & 4.
Windows device manager shows no conflicts.

The main difference I see in the device manager is that
ports 1 & 2 show up as standard ports while 3 & 4 show
up as PCI.

Any thoughts?   Thanks,
Watch Question

Does the PCI card provide true hardware COM ports? If so, they should be detected by BIOS and shown in the summary screen, including I/O address info and IRQ. This could be some kind of software issue (if  the ports are run by software/drivers) or a resources clash (if something is using the ports).

Not the solution you were looking for? Getting a personalized solution is easy.

Ask the Experts


The ports show up under the device manager under PORTS.  The card info states "conforms to PC V2.1 plug and play" and "supports DOS and Windows based software".

So I am assuming that they are true hardware ports.   Device manager shows no conflicts and that they are working OK.  



The PCI card manufacturer provided a new driver and that
took care of it.   Award the points to rid as he responded and
mentioned drivers.

Thanks. Sorry I couldn't be more conclusive. Glad you got it working.
Access more of Experts Exchange with a free account
Thanks for using Experts Exchange.

Create a free account to continue.

Limited access with a free account allows you to:

  • View three pieces of content (articles, solutions, posts, and videos)
  • Ask the experts questions (counted toward content limit)
  • Customize your dashboard and profile

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.


Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.