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

NAME
     udcf - Gude ADS Expert mouseCLOCK DCF77/HBG time signal station receiver

SYNOPSIS
     udcf* at uhub?

DESCRIPTION
     The udcf driver provides support for the Gude ADS Expert mouseCLOCK, a
     receiver for the German DCF77 and the Swiss HBG time signal stations.
     udcf implements a timedelta sensor and the delta (in nanoseconds) between
     the received time information and the local time can be accessed through
     the sysctl(8) interface.

CLOCK TYPE
     The driver automatically detects if it is receiving the German DCF77
     timecode or the Swiss HBG timecode and indicates the clock type in the
     sensor description.  This value will not be changed once set, even when
     the receiver module is changed at runtime.

     DCF77  German DCF77 time signal station (77.5 kHz longwave transmitter
            located in Mainflingen near Frankfurt)

     HBG    Swiss HBG time signal station (75 kHz longwave transmitter located
            in Prangins near Geneva)

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

     OK          The time information is valid and the receiver is fully syn-
                 chronized to the time signal station.  The timedelta is safe
                 to use for applications like ntpd(8).

     WARN        The time information is valid, but there has been a reception
                 or parity error.  The sensor value is adjusted using the lo-
                 cal clock for at most 15 minutes.  The timedelta should be
                 used with care.

     CRITICAL    No valid time information has been received for more than 15
                 minutes.  This is an indication that hardware should be
                 checked to see if it is still functional.  The timedelta will
                 eventually degrade to a lie as all computer internal clocks
                 have a drift.

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

HISTORY
     The udcf driver first appeared in OpenBSD 4.0.

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

OpenBSD 4.0                    January 12, 2006                              1
