[ntp:questions] Re: Errors with NMEA refclock
David L. Mills
mills at udel.edu
Mon Jan 30 19:15:39 UTC 2006
Some drivers use the mode specification to set options such as select
code and line speed. The field is specified as the ttl member normally
used to specify time to live for multicast packets.
David J Taylor wrote:
> Terje Mathisen wrote:
>>Harlan Stenn wrote:
>>>>>>In article <43DD34D3.8000600 at ntp.isc.org>, mayer at ntp.isc.org
>>>>>>(Danny Mayer) writes:
>>>Niall> as far as I can tell only 4800 is supported with the default
>>>Danny> If there's something wrong with the baud rates lets get it
>>>fixed. We Danny> just have to know what's wrong.
>>>There's a reason it's set to 4800. I don't know what the reason is,
>>>but there is a reason.
>>A very good reason indeed:
>>4800 baud is an intrinsic part of the NMEA spec! :-)
>>All devices that talk NMEA do so at 4800.
> You are, of course, correct. However, many devices /do/ allow higher
> speeds (which would provide lower timekeeping jitter), but there is no
> easy way to tell ntpd about the higher speed. I see that flag1 and flag4
> are unused for this driver, so that might be a way to pass the port number
> and baud rate under Windows. E.g. flag4 19200.
> (Perhaps the port number is implied already by the unit number in the
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