[CentOS] USB Serial Ports

Fri Nov 17 15:05:27 UTC 2017
Denniston, Todd A CIV NAVSURFWARCENDIV Crane, JXVS <todd.denniston at navy.mil>

> -----Original Message-----
> From: Chris Olson [mailto:chris_e_olson at yahoo.com]
> Sent: Thursday, November 16, 2017 5:42 PM
> To: CentOS Mailing List
> Subject: [CentOS] USB Serial Ports
> We have several CentOS 6 systems that are used in various configurations
> of test equipment.  One of the primary functions of these systems is the
> connectivity to serial ports of some operational systems that have serial
> port control requirements.  Lack of interface bus slots led us to the use
> of USB connected serial ports on these CentOS 6 systems.
> We first used these USB connected serial ports in our RHEL 5 test equipment
> systems.  With RHEL 5, shut down and boot up of the systems would often
> cause the serial ports to have a different driver name, even though we had
> not changed the ports where the USB devices were plugged in.  This caused
> software access problems until we discovered what could be done using the
> udev rules to lock in the driver names.
> This problem seems to have gone away in our newer systems with CentOS 6,
> and we would like to make sure that it does not return.  We are deploying
> some of the systems and do not want to have software access issues in the
> field where fixes are more difficult.  We would like to know if there is
> some underlying factor that has solved this problem for us.  Any ideas on
> what to check would be greatly appreciated.
I have no idea why it is working better under 6, but it is possible to use UDEV rules to force them to be at expected /dev/my_tty* locations using vendor_ID/device_ID/serial_number combinations.  Once you figure that out, you should even be able to use the same (or at least similar) rules under 7.

Even when this disclaimer is not here:
I am not a contracting officer. I do not have authority to make or modify the terms of any contract.