Campbell Scientific COM220 56k Phone Modem - Manual (Page 19)

COM220 Telephone Modem
enable auto-bauding in the datalogger. If the datalogger BaudrateME is
positive (due to an earlier program instruction or Status table
configuration), the datalogger will be unable to communicate with the
COM220 unless baud rates happen to match. A good rule of thumb is to
keep baud rates negative (–) in programs and when configuring the
Status table to allow datalogger auto-bauding.
5) If unable to connect to a datalogger via the COM220, make sure that the
datalogger is not beaconing to the same port for which the COM220 is
configured (that is, if the COM220 is configured for SDC7 and the
datalogger’s BeaconSDC7 is set to something other than 0, a connection
cannot be established).
6) If the COM220 is in modem enable mode, verify that the COM220 is the
only modem-enable device connected to the datalogger. Other common
Campbell Scientific modem-enable devices are the SC32B, some RF
modems, the MD485, the RF401, the SC932A, and the PDA-to-CS I/O
connector.
7) If the COM220 is in SDC mode (the default is SDC7, with DIP switch 1
closed and DIP switch 2 open), verify that any other SDC devices attached
to the datalogger are using a different SDC address (that is, if the COM220
is configured for SDC7, another SDC device attached to the datalogger
must use SDC8).
8) Verify that no other software application is currently using the same COM
port on the computer. Even if a program is minimized in windows, it may
put a lock on a COM port. Some notebook computers do not
automatically activate the COM ports. Verify that the COM port you are
using is activated.
9) Use the Low Level Log in the Campbell Scientific software, LoggerNet,
[Status Monitor | Tools | Log Tool | View | View I/O (Low Level Log)] to
see connection progress while a link is being established. Assuming the
above items are OK, the Low-Level Log will display “ATDT#######”,
where ####### is the phone number entered in LoggerNet Setup’s Phone
Remote device for the datalogger you are trying to call. The modem
attached to the computer will respond back to the computer with result
codes showing how the call is progressing. These responses should
include “RING” and “CONNECT ####” where #### is the negotiated
modem-to-modem connection baud rate. The maximum baud rate setting
in Setup’s PakBusPort [LoggerNet | Setup | PakBusPort (in the device
map)] device may limit the baud rate selected by the modems since it
defaults to 9600. You can sometimes achieve a higher connection baud
rate by raising the PakBusPort’s maximum baud rate.
10) Can you attach an 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.
11) Verify the COM220 is receiving 12 Vdc. If the COM220 is receiving 12
Vdc from a separate power supply instead of the datalogger, verify that the
ground of the separate power supply is connected to the datalogger’s
ground.
12) Verify the datalogger is turned on.
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