Specifications

COM220 Telephone Modem
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.
If the local telephone company does not provide phone-line
surge protection, a Campbell Scientific surge suppressor should
be used. Refer to Section 3.5 for more information.
NOTE
3.5 Connecting to a Surge Protector
Campbell Scientific offers two surge protectors (CSI model 4330 and CSI
model 6362). The 4330 and 6362 are essentially the same, except the 6362 has
hardware for mounting to an enclosure backplate.
The 4330 is also known as the 2374-01.
NOTE
The 4330 and 6362 have a protector element for each line that consists of a
heavy-duty-rated, two-element gas tube, an external backup gap assembly, and
a switch-grade shorting mechanism. The gas tubes (tip and ring) are sealed in
a fire-resistant plastic body. DC Breakdown @ 100 V/sec is 300 to 500 volts;
DC extinguishing @ 52 V, 135 V, and 150 V is less than 150 milliseconds.
Figures 5 and 6 show the wiring for connecting the surge suppressor. Color
coding of wires may vary. The important consideration is to follow TIP all the
way through and RING all the way through. Getting wires crossed typically
does not damage anything. The phone line just will not work until the wires
are straightened out.
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