Guralp Systems CMG-DCM - Manual (Page 8)

CMG-DCM Data Communications Module
1.1 Inside the DCM
The DCM's configuration is maintained by an internal database. All of
the flexibility of the unit is provided through this configuration
database. Before you deploy the DCM, you will need to configure it for
your needs, either using its on-board Web server or over a direct serial
link.
The two main areas which need to be configured determine the
different services which the DCM provides from its serial and network
ports.
Serial port services
You can use either the DCM's console or its Web configuration
interface to configure the serial data ports. The serial.x.service
configuration option determines which service each port provides.
•
The simplest service is getty. This creates a console port, which
you can use to log in to the Linux operating system of the DCM
directly.
•
The mgetty-r service is similar, but is more suited for serial links
including modems, in which the link is not always active. This
is the default option.
•
Any of the serial ports on the DCM can be directed to transmit
GCF (Güralp Compressed Format) data by setting the service for
that port to
gcf_out. You can then run Scream! or other software
on your computer to receive the data. You will not be able to
access the Web configuration interface using this service,
although you may be able to configure attached digitizers from
Scream!.
•
Likewise, any serial port can be set to listen for incoming data
( e.g. from a connected digitizer or another DCM) by setting the
service to gcf_in. The DCM will automatically combine this data
with any other streams it is receiving, and send it on using all
gcf_out ports and any other transmission methods which have
been configured.
•
You can log in to the Linux operating system over a modem link
by setting the service to
mgetty. mgetty listens for incoming calls
from your computer and sets up a login session for you. You
may need to configure minicom or hypertrm to communicate
with your own modem before you can do this.
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