Guralp Systems CMG-DCM build <10,000 - Manual (Page 87)

Operator's Guide
The “Ports” section of the web page allows control of the baud rates of
the digitiser's serial ports:
For a stand-alone digitiser or digital instrument, the “GPS” and “Data
in” ports are exposed on external connectors. The “Data out” port is
assumed to be connected to the CMG-EAM, CMG-DCM or CMG_NAM
and the rate set here must match that set for the appropriate serial port
(see section 9.1 on page 97 for details of reconfiguring serial ports).
If a stand-alone digitiser or digital instrument is fitted with a Lantronix
Ethernet or WiFi option, it uses the “Data out” port settings for its
internal communications with the digitiser. Changing the associated
baud rate requires making a network connection to the Lantronix
unit's web interface and selecting the matching baud rate from its
control page.
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Note: For CMG-DAS systems, the digitiser's “Data out” port is
connected internally to the CMG_EAM module's “Port A” and
both ports must use the same Baud rate. The digitiser's “Data
in” port is used to provide a console for the digitiser (without
interrupting seismic data transmission) and is connected
internally to the CMG_EAM module's “Port B”. Again, both
ports must use the same Baud rate. The digitiser's “GPS” port is
connected to the CMG_EAM module's “Port C”. This
connection can be used in two ways: the CMG-EAM module
can share with the digitiser the data from the physical GPS
receiver and use it as an NTP clock source (see section 6.3 on
page 64); or, alternatively, the CMG-EAM module can be
synchronised to another time source (such as Internet NTP) and
provide NMEA signals to the digitiser module. In either case,
The digitiser module's “GPS” port and the CMG-EAM module's
“Port C” must use the same Baud rate.