Campbell Scientific DC112 User Manual

INSTRUCTION MANUAL

DC112 Modem

Revision: 12/91

Copyright (c) 1987-1991

Campbell Scientific, Inc.

Warranty and Assistance

The DC112 MODEM is warranted by CAMPBELL SCIENTIFIC, INC. to be
free from defects in materials and workmanship under normal use and service
for twelve (12) months from date of shipment unless specified otherwise.
Batteries have no warranty. CAMPBELL SCIENTIFIC, INC.'s obligation
under this warranty is limited to repairing or replacing (at CAMPBELL
SCIENTIFIC, INC.'s option) defective products. The customer shall assume all
costs of removing, reinstalling, and shipping defective products to CAMPBELL
SCIENTIFIC, INC. CAMPBELL SCIENTIFIC, INC. will return such
products by surface carrier prepaid. This warranty shall not apply to any
CAMPBELL SCIENTIFIC, INC. products which have been subjected to
modification, misuse, neglect, accidents of nature, or shipping damage. This
warranty is in lieu of all other warranties, expressed or implied, including
warranties of merchantability or fitness for a particular purpose. CAMPBELL
SCIENTIFIC, INC. is not liable for special, indirect, incidental, or
consequential damages.

Products may not be returned without prior authorization. The following
contact information is for US and International customers residing in countries
served by Campbell Scientific, Inc. directly. Affiliate companies handle repairs
for custome rs within their territorie s. P lease visit www.ca m pbells ci.com to
determine which Campbell Scientific company serves your country. To obtain
a Returned Materials Authorization (RMA), contact CAMPBELL
SCIENTIFIC, INC., phone [phone]. After an applications engineer
determines the nature of the problem, an RMA number will be issued. Please
write this number clearly on the outside of the shipping container.
CAMPBELL SCIENTIFIC's shipping address is:

CAMPBELL SCIENTIFIC, INC.

RMA#_____
815 West 1800 North
Logan, Utah 84321-1784

CAMPBELL SCIENTIFIC, INC. does not accept collect calls.

1. FEATURES

• Bell 212A and CCITT V.22 Compatible

• Full Duplex at 300 and 1200 Baud

• "AT" Command Set

• RJ-11C Telephone Jack

• Pulse or Tone Dialing

• Direct Connection to and powered by:

- CSI dataloggers

- CSI PC201 Card in IBM PC Compatible

- Computer

- CSI PC203 Power-up Control Box

- CSI SC532 RS232 Interface

• Signal Level Connects/Disconnects 5Vdc
External Power minimizing current drain

2. DESCRIPTION

The DC112 Modem is a 300/1200 baud modem
employing the popular "AT" command set. Its
primary use is as a remote site modem
connected to a CSI datalogger. The modem is
powered and enabled by the battery-powered
datalogger. When disabled, the DC112 draws
less than 2 uA from the datalogger 5 Vdc
output.

A Hayes or Hayes compatible modem is used at
the computer site.

DC112 MODEM

FIGURE 1. Connector Pinout

4. (output) Rx Data- serial data from modem.

5. (input) Modem Enable- a logic high turns
on 5V power to the modem. A logic low
shuts off 5V power to the modem.

6. (input) Serial Device Enable - a logic high
disables communication with the modem
without removing power or changing the
modem's mode. This input can be negated
with an internal jumper.

7. No Connection

8. No Connection

9. (input) Tx Data- serial data to the modem.

The DC112 can be used as an originate modem
at the datalogger site. To originate a call to the
computer, the datalogger is programmed using
Instruction 97. For more information refer to the
datalogger manual, Instruction 97.

The DC112 is connected to a CSI datalogger by
using a 9-pin subminiature D connector cable.
The pinout of the connector is shown in Figure

1. The pins used by the modem are (all levels
are OV for logic low, 5V for logic high):

1. (input) +5 V regulated supply

2. (input) Ground

3. (output) Ring- a logic high signifies a ring
signal has been detected.

3. SPECIFICATIONS

Current Drain: Approximately 2 uA when
modem enable is low; 35 mA when modem
enable is high but phone is on-hook; 48 mA
when off-hook.

Supply Requirements: A single 5 V regulated
power supply.

Logic Levels: Below 1.5 V inputs a low state
and above 3.5 V inputs a high state. A low
voltage level on the Tx data input (pin 9) and Rx
data output (pin 4) represents a mark.

o

Operational from -25
Size: 4 3/8" x 3" x 1"
Weight: 12 oz.

C to +50oC

1

DC112 MODEM

4. INSTALLATION

Your DC112 is designed to be used on standard
device telephone lines. The DC112 connects to
the telephone line by means of a USOC RJ11C
jack. Connection to telephone company­provided coin service (central office
implemented systems) is prohibited.
Connection to party lines service is subject to
State tariffs.

Connect the cable from the telephone jack to
the modem Figure 2. Connection to the
datalogger is done with a Campbell Scientific
SC12 Cable. Connect the 14 awg grounding
wire (provided with the DC112) to the grounding
terminal (GND) on the DC112 and to the
datalogger ground. If the enclosure has a
grounded bus bar, then connect the ground wire
to the bus bar instead of the datalogger ground.
The datalogger ground should be tied to earth
ground. See the grounding section of the
datalogger manual.

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 these changes
might affect your service or the operation of
your equipment, the telephone company will
give you notice, in writing, to allow you to make
any changes necessary to maintain
uninterrupted service.

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.

In certain circumstances, it may be necessary
for the telephone company to request
information from you concerning the equipment
which you have connected to your telephone
line. Upon request of the telephone company,
provide the FCC registration number and the
ringer equivalence number (REN) of the
equipment which is connected to your line; both
of these items are listed on the equipment label.
The sum of all of the REN's on your telephone
lines should be less than five in order to assure
proper service from the telephone company. In
some cases, a sum of five may not be usable
on a given line.

FIGURE 2. RJ11C Phone Modem Connections

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DC112 MODEM

Remote datalogger installations require a
telephone surge protector (Model 2372-01)
unless the telephone company confirms a surge
protector has already been installed at the
remote site (Figure 3). Connect the 14 awg
grounding wire (provided with the DC112) to the
grounding terminal (GND) on the DC112 and to

the datalogger ground. If the enclosure has a
grounded bus bar, then connect the ground wire
to the bus bar instead of the datalogger ground.
The datalogger ground should be tied to earth
ground. See the grounding section of the
datalogger manual.

FIGURE 3. Burial Phone Line to Remote Telephone Modem

3