Guralp Systems CMG-DCM build <10,000 - Manual (Page 93)

Operator's Guide
8.4 Using NTP with Authenticated Digitisers
Please see the discussion of synchronisation options available with
Authenticated Digitisers in the previous section.
The data flow when NTP is used as the primary clock source is
illustrated below:
To configure the NTP subsystem, see section 6.3 on page 64.
To configure NMEA output, see section 8.6 on page 94.
8.5 Configuring NMEA as an NTP clock source
To configure NTP to use NMEA as a clock source, two steps are
required. First, tick the Acquire time from connected GPS check-box
in the NTP configuration page as described in section 6.3 on page 64.
Secondly, configure the relevant serial port as an NMEA input.
To do this, using the web interface, select “Serial ports” from the
“Configuration” → “All options” menu or select the “Serial ports”
short-cut from the “Configuration” → “Data transfer/recording options”
menu. To configure an NMEA input from the command line, start
gconfig and select “Serial ports” from the top level menu.
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Note: The external GPS connector is disconnected when Port C
of the EAM is set to “NMEA Out” and connected to the
digitiser's GPS input in all other cases.