Campbell COM200A, Instruction Manual, Page: 9 / 22

COM200A TELEPHONE MODEM
5
4. TROUBLESHOOTING
When the Campbell Scientific software cannot
establish a link to the remote datalogger that is
connected to the COM200A, check the
following:
1) Verify the modem initialization settings have
been changed for the specific calling
modem on the computer. See software
manual and/or help screens for more
information.
2) Verify nothing else is using the same COM
port on the computer. Even if a program is
minimized in windows, it may have a lock
on the COM port. Some notebook
computers do not automatically activate the
COM ports. Verify the COM port you are
using is activated.
3) The Campbell Scientific software will
display an activity of communication as the
link is being established. Assuming the
above items are O.K., the software should
display in the activity window/screen
something such as “ATDT#######”.
Where the #### is the telephone number
listed in the dialing path of the software for
the datalogger you are trying to call.
The local modem attached to the computer
will respond back to the computer with
result codes depending on how the call is
progressing. These result codes can be
either numeric (0, 1, 2, etc.) or “verbose”
(“OK”, “CONNECT”, “RING”, etc.). Our
software expects numeric result codes.
The result codes may appear on a new line,
be appended to the last line, or may even
replace the first letter(s) of the last line. If
these characters are verbose, the
initialization string for the modem will need
to be changed. Appendix A has a list of
possible result codes. The result code
returned may indicate why the call is
unsuccessful.
4) Can you attach a normal analog telephone to
the line and make a call out? If not, contact
your local telephone company. If you can
make a call out but the connection is poor or
faint, contact your local telephone company.
5) Verify the COM200A is receiving 12 VDC.
If the COM200A is receiving 12 VDC from a
separate power supply instead of the
datalogger, is the ground of the separate
power supply connected to the datalogger’s
ground?
6) Verify the COM200A is the only Modem
Enable device connected to the datalogger.
Other common Campbell Scientific modem
enable devices are the SC32A, some RF
modems, and the MD9.
7) Verify the datalogger is turned on.
All repairs on the COM200A modem must be
performed by Campbell Scientific, Inc. or an
authorized agent of Campbell Scientific, Inc.
For assistance in installation, troubleshooting,
or for repair, contact Campbell Scientific:
Campbell Scientific Australia
P.O. Box 444
Thuringowa Central
Townsville QLD 4817
Australia
Telephone: 61-7-4725-4100
Fax: 61-7-4725-4155
Web site: http://csa.ultra.net.au/
5. MODEM SETTINGS IN NON-
VOLATILE MEMORY
The COM200A comes from the factory with the
appropriate settings for most applications. It is
programmed to answer the call as soon as it
detects the call.
One may modify the COM200A’s settings in
non-volatile memory using Hayes AT
commands. Appendix A describes the
procedures and commands required to make
the changes described in this section.
Some of the settings one may change are:
Disable auto-answer: This option is used only
when the modem is not to answer a call. For
example, the COM200A is connected to a
telephone line which is to be used part time for
voice communication. In this situation it is best
to have the datalogger call the computer.
Answer on X
th
ring: This option is used when
the modem is sharing a line and you only want it
to answer after a specified number of rings. For
example, the COM200A is sharing a line with
people at an office. It can be programmed to