---
name: "umbg"
section: "4"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["openbsd"]
url: "https://new.carta.tech/umbg"
---

# umbg(4)

Meinberg Funkuhren USB5131 and DCF600USB timedelta sensors

## NAME

**umbg** – Meinberg Funkuhren USB5131 and DCF600USB timedelta sensors

## SYNOPSIS

**umbg\* at uhub?**

## DESCRIPTION

The **umbg** driver provides support for Meinberg Funkuhren USB5131 and DCF600USB time signal receivers for the German DCF77 station. **umbg** 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)](/sysctl/8.md) 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)](/ntpd/8.md).

- 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 itself:

- OK

  The clock is synchronized.

- WARN

  The device's clock is free running on the local oscillator. 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)](/intro/4.md), [usb(4)](/usb/4.md), [ntpd(8)](/ntpd/8.md), [sysctl(8)](/sysctl/8.md)

## HISTORY

The **umbg** driver first appeared in OpenBSD 4.3.

## AUTHORS

The **umbg** driver was written by Marc Balmer ⟨*mbalmer@openbsd.org*⟩.