LDM422 Datasheet, PDF (1/4 Pages) List of Unclassifed Manufacturers – Fully Isolated Limited Distance Modem, RS-232/422 Converter

LDM422
Fully Isolated
Limited Distance Modem,
RS-232/422 Converter
Description
The LDM422 is a compact RS-232 to RS-422 converter which features
a complete electrical isolation barrier and heavy duty electrical surge
protectors. These devices feature a rugged aluminum enclosure small
enough to mount on the back panel of typical computer equipment,
saving valuable desk and floor space. Isolation is provided by optical
couplers and a DC-to-DC converter. The RS-232 connection is through
male or female EIA 25-pin connectors. The RS422 connections are
made through convenient solderless screw terminals.
The LDM422 series is designed for full duplex operation over two-
wire pairs. Outputs are tri-state, allowing multidropping of up to 32
units. Hardware handshake is available over two separate wire pairs.
Data rates are 75 to 19,200 baud. Six diagnostic LED indicators are
provided (see Figure 1) for installation guidance and system
troubleshooting. The RS-232 interface supports Request To Send,
Clear To Send, Data Set Ready, Received Line Signal Detect, and
Data Terminal Ready. A convenient null modem switch is provided for
the data lines. The RS-422 interface supports Request To Send and
Clear To Send on separate wire pairs. The LDM422 may be used to
convert two sets of send and receive channels by using RTS and CTS
circuits as the second data channels. Data rates are the same. The
units use 12VAC from a wall-mounted transformer or ±12VDC to
pins 9 (+) and 10 (–) of the RS-232 connector.
Features
Á COMPLETE ISOLATION WITH OPTICAL
COUPLERS AND POWER DC-TO-DC
CONVERTER
Á INDUSTRIAL SURGE PROTECTION DEVICES
Á SIX LED DIAGNOSTIC INDICATORS
Á DC TO 19,200 BAUD AT 6000 FEET (1800M),
9600 BAUD AT 3 MILES (5KM)
Á REQUEST-TO-SEND, CLEAR-TO-SEND
HANDSHAKE
Á TRI-STATE OUTPUTS FOR MULTIDROP
APPLICATIONS
Á SELECTION OF CONNECTORS
Á WIDE OPERATION TEMPERATURE RANGE
Á SOLDERLESS SCREW TERMINAL FIELD
CONNECTIONS
Dataforth does not authorize or warrant its products for use in life support/critical applications.
Specifications
Model
Baud Rate Range
Baud Rate
Distance (miles)
Distance (km)
Maximum Multidrop
Units
Common Mode
Isolation
Differential Mode
Surge Protection
(9 devices)
Channel Lines⁽¹⁾
Control Lines⁽¹⁾
Modes
LDM422
0 – 19.2K
19.2K 9.6K 4.8K
1.14
3
4
1.8
5 6.7
2.4K 1.2K – 0
5
7
8.3 11.7
32. Reduced distances may be required when as
many as 32 units are multidropped. No restrictions
apply for distances of 1 mile (1.7 km) or less.
Surge: 750V
Continuous: 500V
(AC input)
ANSI/IEEE C37.90.1-1989
(all RS-422 inputs and outputs)
TD, RD, RTS, CTS
RTS, CTS, DTR, DSR, RLSD
Asynchronous 4-wire duplex, 2-wire half-duplex,
2-wire simplex
18
Model
LDM422
Null Modem Switch
1 (Reverses RS-232 pins 2 and 3)
RS-422 Output Drive 20mA min/output
RS-422 Input Impedance
Power:
AC operation⁽²⁾
DC operation
6kΩ min/input
12VAC, ±10%, 10W screw terms 1 & 2
+11.5VDC to +17.0VDC @ 400mA on pin 9
-11.5VDC to -17.0VDC @ 400mA on pin 10
Operating Environment 0°C to +70°C 0 to 95% relative humidity,
noncondensing
Dimensions
6.6 in x 2.1 in x 1.28 in
(167.6 mm x 53.3 mm x 32.5 mm)
Weight
PT3 and PT3E
7 oz (200 g) max
11.0 oz (311.8 g) max
MTBF⁽³⁾
>100,000 hrs
Notes: (1) TD = Transmit Data, RD = Receive Data, RTS = Request To Send, CTS =
Clear To Send. DTR = Data Terminal Ready, DSR = Data Set Ready, RLSD = Received
Line Signal Detect. (2) 120VAC and 220VAC power transformers are available. (3) Ground-
benign environmental conditions (no salt atmosphere, <50°C ambient temperature).
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