[time-nuts] Serial port splitter s/w

Paul tic-toc at bodosom.net
Wed Feb 26 13:24:10 EST 2014


On Wed, Feb 26, 2014 at 12:32 PM, Chris Albertson <albertson.chris at gmail.com
> wrote:

> You can NOT control a GPS from two ports.  Both NTP and LH will try to
> send commands to the GPS.
>

Actually the Palisades driver doesn't send commands to the Thunderbolt.  It
sends a single invalid command requesting auto messages and then parses the
data stream.  As long as primary timing packets are received it works.  A
Thunderbolt will wake up doing the right thing and if not I believe LH will
correctly initialize it.

The deeper point is correct and the Trimble devices I have experience with
have ~100ms of jitter.

Props to Jackson Labs -- my Fury has O(10) microseconds of jitter using
NMEA messages.  If only they were $100.



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