Using with Campbell Scientific Dataloggers
8.1 Configuring a Desk-Top Modem as a Base Station
You can use most desktop landline and even cellphone modems to connect to a
remote COM110 modem. The modem should be setup as if calling a remote
landline modem. The baud rate for connection should be set to 9600 minimum.
The modem can be configured to connect either via the TAPI or Phone modem
settings (TAPI being the preferred option if you have installed the modem into
your Windows environment.)
While Campbell Scientific Ltd may be able to give some advice as
to the best settings to use for common modems, the connection of
the landline modem to a cellular network is specific to the cellular
network being used. Problems establishing the connections are often
not related to the fact that a COM110 modem or datalogger are
connected at the remote end of the connection, but are caused by
compatibility issues of the PC modem with the network. Please also
contact your cellular network support team for advice on any
problems that you might encounter.
8.2 Configuring the COM110 modem as a Base Station using
Loggernet
Neither Campbell Scientific nor the manufacturer provide specific drivers for the
COM110 modem. Instead they recommend that you follow the normal Windows
procedure for installing a TAPI modem and select the modem type “Standard
9600 bps” or “Standard 19200 bps”. Check that Windows finds the modem and
attaches it to the correct COM port. For this to work you must make sure the baud
rate of the modem has been setup previously to match the modem type selected.
Thereafter you can use the modem to call-out using the TAPI interface.
You can also use the Phone modem option in Loggernet, using the default modem
type, with the baud rate set to 9600 baud. This option is preferred if additional
modem settings are required (see below) or if the COM110 modem is often
unplugged from the PC, as the TAPI interface expects to find the modem
connected at all times.
Before use it is also necessary to reconfigure the modem back to its
factory default settings using a terminal emulator and issuing the
AT&F, AT+1FC=2,2, then the AT&W commands.
8.2.1 Extending the Default Time-Outs
When using either a landline base modem or a COM110 modem as the base, it is
sometimes necessary to increase the time both the PC and the base modem will
wait before timing out an attempted connection to a remote modem. Many
modems have a default timeout of 30 seconds which may not be long enough for
connection over busy or distant networks. Adding “S7=45” to the end of the
modem initialisation string sets the timeout at 45 seconds and Loggernet will
increase its own timeouts to suit. Normally you are allowed to increase this setting
up to 60 (seconds) if a call is seen to take such a long time to connect. Setting too
long a delay may, however, slow down the retry sequence in the event of a failed
connection.
NOTE
NOTE
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