Guralp Systems CD1.1 - Manual (Page 39)

Operator's Guide
link, it will be recovered and retransmitted later when the DC
sends an acknack frame.
Whenever any frame is transmitted, it is assigned a sequential
sequence number. A second database file, the framedb,
records the sequence numbers against the time-stamps of the
frames being transmitted. The DC periodically produces an
acknack frame which indicates which of those frames have
been successfully received; once a frame has been
acknowledged, it is purged from the frame database file.
If the acknack frame indicates that the DC has a gap, the frame
database file is consulted to find the time-stamp of the missed
frame(s), and those frames are added to the list for
retransmission.
Tools are provided to maintain the two database files. See
Section 9.2 on page 56 for more details.
7.2 Creating a new CD1.1 sender instance
In the web interface, select “Configuration -> Services” from
the left-hand menu or from the command line, run
gconfig
and then select “System services”.
Now choose “data-out-cd11 -- CD1.1 sender” to view a list of
configured sender instances. You can choose to either
configure any existing instance (as described in the following
section) or select “Create new service instance” to create a
new one.
A form is displayed which allows you to set various parameters
for the instance. The default values are suitable for most
applications but each parameter is discussed in the following
section. After entering the desired configuration for the
instance, choose Submit.
This will create (if it is new) and configure the sender instance.
If it is not already running, you can start it by using “Control ->
Services” on the web menu or by running
/etc/init.local/data-out-cd11.0 start
from the command line.
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