Campbell Hausfeld COM220 - Manual (Page 11)

COM220 Telephone Modem
You can modify the following COM220 settings with DIP switches:
1) Communication mode (e.g., SDC or Modem Enable)
2) ME baud rate
3) PakBus ready
Additional changes (see examples below) may be modified with Hayes AT
commands. Appendix A.2 describes the procedures and commands required to
effect the changes described in this section.
Some of the AT command 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 COM220 is connected to a telephone line that
is to be used part time for voice communication. In this situation it is best to
have the datalogger call the computer.
Speaker On/Off and Volume: Default settings have the speaker on only
during call establishment and set to a low volume. The speaker may be turned
completely off in order to limit the current drain during the connection or so
you don’t hear the speaker. It is also possible to set the speaker volume higher,
if you want to hear the speaker better than the default low volume setting.
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 COM220 is sharing a line with people at an office. It can be programmed
to only answer after the third ring. If the PC calls when the office is closed and
no one answers the phone after three rings, the datalogger will pick it up.
Change telephone system types: Change from the Bell 212A (U.S. and
Canada) system to a CCITT V.32 (foreign, 9600 baud) or CCITT V.22
(foreign, 1200 baud) system. This does not mean that the COM220 is tested
and approved for all foreign countries.
CITT is an international consultative committee that sets international
communications usage standards. V.32 and V.22 are CCITT standards that the
COM220 meets.
5. Troubleshooting
When the Campbell Scientific software cannot establish a link to a remote
datalogger that is connected to a COM220, check the following:
1) Verify that the modem initialization settings on your computer are correct
for your specific calling modem (i.e., the modem attached to your
computer). See the calling modem’s software manual and/or help screens
for more information.
2) If using a non-PakBus datalogger (e.g., CR510, CR10X, CR23X, CR7,
CR5000 with array-based operating system), verify that DIP switch 5 on
the COM220 is in the CLOSED position. For PakBus dataloggers (e.g.,
CR800, CR850, CR1000, CR3000, CR10XPB, CR23XPB, CR510PB),
DIP switch 5 should be open. See Appendix A.1 for details.
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