UMBG(4)                   OpenBSD Programmer's Manual                  UMBG(4)

NAME
     umbg - Meinberg Funkuhren USB5131 timedelta sensor

SYNOPSIS
     umbg* at uhub?

DESCRIPTION
     The umbg driver provides support for the Meinberg Funkuhren USB5131, a
     time signal station receiver for the German DCF77 station.  umbg imple-
     ments a timedelta sensor and the delta (in nanoseconds) between the re-
     ceived time information and the local time can be accessed through the
     sysctl(8) interface.

     The quality of the timedelta is reported as the sensor status:

           UNKNOWN     No valid time information has been received yet.

           OK          The time information is valid and the timedelta is safe
                       to use for applications like ntpd(8).

           WARN        The time information is still valid, but no new time
                       information has been decoded for at least twelve hours
                       due to a reception or parity error.  The timedelta
                       should be used with care.

           CRITICAL    No valid time information has been received for more
                       than twelve hours since the sensor state degraded from
                       OK to WARN.  This is an indication that hardware should
                       be checked to see if it is still functional.

     A second sensor provides the relative signal quality as a percentage.
     The status of this sensor is used to report the status of the device it-
     self:

           OK          The clock is synchronized.

           WARN        The device's clock is free running on the local oscil-
                       lator.  This is not an error and can happen due to the
                       nature of the signal transmission using longwave radio.

           CRITICAL    Hardware failure, e.g. communication with the device
                       failed.

SEE ALSO
     intro(4), usb(4), ntpd(8), sysctl(8)

HISTORY
     The umbg driver first appeared in OpenBSD 4.3.

AUTHORS
     The umbg driver was written by Marc Balmer <mbalmer@openbsd.org>.

OpenBSD 4.7                    November 11, 2007                             1
