serial consoles

Matthew Luckie mjl at
Sat Dec 24 18:08:54 UTC 2011

On 12/25/11 04:45, Warren Block wrote:
> On Sat, 24 Dec 2011, Matthew Luckie wrote:
>> However, when I use cu on the laptop:
>> sudo cu -l /dev/cuaU0 -s 9600
>> I never get a login prompt. If I press enter, the cursor scrolls down.
>> Likewise other characters echo back. I'm reasonably sure that I'm
>> connected to the appropriate com port on the server because if I plug
>> it into the other com port and press enter, nothing happens.
> Might there be something else on the server using/trying to use that com
> port at the same time, like apcupsd?
> Running cu on the server (after resetting the config) would allow
> manually typing characters to see if they come out of the right port.

Thanks for your reply, Warren.

I do run apcupsd, though it uses a usb port for communications with the 
UPS and is configured to do so.  I turned apcupsd off in rc.conf, as 
well as commented out the getty line for the port, and rebooted the 
system.  Then, I used cu on the server and found characters were sent 
both ways over the serial cable.

I then added the /etc/ttys entry back and rebooted.  When I used cu on 
the laptop it behaved as before -- i.e. no login prompt.  If I tried 
using cu on the server, it timed out after about 10 seconds and said 
"link down".

Any further tips?  I've put the server's apcupsd.conf, /etc/rc.conf, and 
dmesg.boot at


More information about the freebsd-questions mailing list