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Need to use a lower # COM port to support a USB or BT device
Posted: Mon Jul 29, 2013 4:15 pm
by bighank
Have T61p and W500 with internal BT adapters and a T61 with a BT dongle. When I connect either a USB or BT scan tool device with a ELM327 chip to the laptops it connects at COM port 20 or above. All COM ports with lower numbers are "IN USE". The programs which I am trying to use with this hardware are hard coded to look for ports 2-8 or 2-15 and as a result will not connect to the ELM327. I have both USB and BT versions of the ELM327 OBDII scan tool readers. One program will connect to the ELM327 but is not very robust and will not give me the information I need but I know that the ELM327s are working.
How can I connect to a lower number port without trashing my system or killing some device currently using the lower number ports?
Re: Need to use a lower # COM port to support a USB or BT device
Posted: Mon Jul 29, 2013 9:03 pm
by rkawakami
It might help to know exactly what OS you're running...
Also, locked duplicate thread in W500 forum. Will move this one to appropriate OS or General Hardware/Software forum when it's clear.
Re: Need to use a lower # COM port to support a USB or BT device
Posted: Tue Jul 30, 2013 5:51 am
by RealBlackStuff
You may have other programs using COM-ports, that are blocking it.
Get
Process Monitor from M$ to find out:
http://technet.microsoft.com/en-us/sysi ... 96645.aspx
Re: Need to use a lower # COM port to support a USB or BT device
Posted: Wed Jul 31, 2013 8:28 am
by hhmcsv
I have come upon this problem regularly. My solution is simply to ignore the "in use" flag in device manager and using a port number which the application will accept, in my case frequently COM4. Unless of course that you have a running application that is actually using the ports.......................

Re: Need to use a lower # COM port to support a USB or BT device
Posted: Sun Aug 04, 2013 5:28 pm
by bighank
Have gone into profile and changed COM ports to COM2 and COM4. It appears to take it even though it warns me that other devices won't work. Problem: No program will recognize the USB or BT device assigned to the lower port. One program I have which will find the device on COM port 20 fails to find it after setting it to COM 2 or COM 4.
Any suggestions?