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COM220 Telephone Modem
TABLE 1. Dataloggers that Require Direct
12 VDC Connection to COM220
CR10(X) with silver wiring panel
CR10(X) with black CR10 wiring panel (P/N
8032)
21X(L)—serial number 13,442 or lower
CR500⎯serial number 1764 or lower
CR7—700X serial number 2778 or lower
3.2 Connecting to Earth Ground
Connect the green 14 awg grounding wire (provided with the COM220) to the
ground terminal (GND) on the COM220 and to the enclosure’s earth ground
connection. If the site does not have a grounded enclosure, then connect the
ground wire directly to an earth ground connection. The datalogger ground
should also be tied to the earth ground.
The modem must be grounded for its transient protection
to work.
CAUTION
3.3 Telephone to MD485 or Telephone to RF Systems
Telephone to MD485 or telephone to radio configurations can be utilized for
communicating with multiple dataloggers through one telephone line. For
telephone to MD485 or telephone to radio communications (with no datalogger
router), the COM220 should be set for ME mode. The COM220 and MD485
should be set to the same baud rate. When using a PakBus network with a
datalogger configured as a router, the COM220 can be set for SDC7 and the
radio for SDC8, or vice versa. Contact a Campbell Scientific Applications
Engineer for more information. In addition, Appendix A.4.4 includes example
programs for both a router datalogger and a remoter datalogger communicating
by telephone to MD485 or telephone to radio.
3.4 Telephone Service
The goal of the telephone company is to provide you with the best service it
can. In order to do this, it may occasionally be necessary for them to make
changes in their equipment, operations, or procedures. If you have any
questions about your telephone line, such as how many pieces of equipment you
can connect to it, the telephone company will provide this information upon
request. If the telephone company requests information concerning the
equipment which you have connected to your telephone line, the FCC
registration number and the ringer equivalence number (REN) of the COM220
are listed on its label. Additional technical information from the FCC and IC on
the COM220 is available in Appendices D and E, respectively.
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