[ntp:questions] Re: Sure RPC DCF77 clock under Linux?

Ulrich Mueller ulm at kph.uni-mainz.de
Sat Jan 7 09:04:11 UTC 2006

Hauke Lampe wrote:

> I have an old Sure serial DCF receiver (small grey box with a single
> red LED) connected to my gateway computer and it works quite well.

The box that I have has a black case, marked "RPC-Modul Made in
Germany". According to Linum Software the grey box is an older

> My main problem is interference. Watch the LED light. Does it show a
> regular pattern of one blink every second, some shorter, some longer?

Yes, the LED pattern is very regular and the receiver is at a safe
distance (approx. 10 m) from the computer.

>From the pattern of the telegrams (see my previous posting) I would
conclude that the reception is o.k., but somehow an additional bit
(or pulse?) gets inserted at the beginning. BTW, the same happens with
the dcfd program.

Maybe I should use an oscilloscope and look at the pulse train from
the receiver?

> FWIW, here is the output of "stty -a -F /dev/refclock-0":

Identical here, except for an additional "-iutf8".

> and the entry in ntp.conf:
> | server mode 16 prefer maxpoll 6

I don't have the "prefer maxpoll 6" but that should not matter.

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