[CentOS] USB Serial ports (ttyACMn) CentOS 6.7 (64-bit) vs. CentOS 6.7 (64-bit)

Thu Feb 4 21:13:33 UTC 2016
Robert Heller <heller at deepsoft.com>

I have two computers: both running CentOS 6.7, 64-bit, with 
kernel 2.6.32-573.12.1.el6.x86_64.  One is a laptop with an 2 core Intel 
processor and the other is a desktop machine with a 4 core AMD processor. Both 
with selinux enabled.

I have a USB serial port device (a RR-CirKits LCC-Buffer USB).  On the desktop 
I am getting this error:

sauron.deepsoft.com% sudo minicom
Device /dev/ttyACM0 access failed: No such file or directory.
sauron.deepsoft.com% dir -lZ /dev/ttyACM0
crw-rw----. root dialout system_u:object_r:tty_device_t:s0 /dev/ttyACM0

But it is working on the laptop!

gollum.deepsoft.com% dir -lZ /dev/ttyACM1
crw-rw----. root dialout system_u:object_r:tty_device_t:s0 /dev/ttyACM1

Same kernel, same device (except it is showing up as ttyACM1 on the laptop).

What is going on here?

Robert Heller             -- 978-544-6933
Deepwoods Software        -- Custom Software Services
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