[LinuxPPS] ntpd doesn't recognize my PPS signal

[Thorsten M.]

On Fri, 17 Oct 2008 14:23:43 +0200
"Luca Bertagnolio" <time at berta.com> wrote:

> What I find a little odd is the fact that there is a difference of 3-4
> counts between your sequence numbers, not sure what that might be
> related to.

I think this was related to the testing procedure, as I've switched the PPS
cable between TTL level and RS232 level signal. The difference was not there before.

> I'd focus my attention of ntpd.  What device produces the PPS signal?
> I have an NMEA+PPS GPS so I use driver #20, and not #22.

I'm using a Meinberg DCF77 PCI511 card:
http://www.meinberg.de/english/products/pci511.htm
From the manual:
"Pulse outputs
The radio clock PCI511 generates pulses whenever a new second (P_SEC) or a new
minute (P_MIN) begins. The P_SEC pulse is available with TTL level (0/+5V) and
RS-232 level (-3..12V/+3..12V), the P_MIN signal with TTL level only."

"PULSE-
OUTPUTS: Pulses every second (PPS) with
         TTL- and RS232-level, pulse duration 100 msec, active high
         Pulses every minute (PPM) with
         TTL- level, pulse duration 100 msec, active high"