Campbell Scientific DC112 Telephone Modem - Manual (Page 3)

1
DC112 MODEM
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.
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.
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.
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.
Operational from -25 o C to +50 o C
Size: 4 3/8" x 3" x 1"
Weight: 12 oz.