485SD9RJ4500 - pg. 1/1
B&B Electronics Revised November 2000
This product designed and manufactured in USA of domestic and imported parts by
Signals From RS-232 Devices
Travel 4000 Feet On Phone Wires
Includes Send Data Control
CE
CE
CE
CE
Model 485SD9RJ
The 485SD9RJ is a port-powered, half-duplex RS-232 to RS-485 converter with send data control. The unit converts TD and RD RS-232
lines to balanced RS-485 signals and supports two-wire RS-485 communications only. The converter is powered from the RS-232 handshake
lines, RTS, CTS and DTR, DSR, CD. The handshake lines are looped back on each other and can be in either state. No handshake change
is necessary so no software is required to control the lines. The RS-485 driver is enabled with each bit of data. The RS-485 receiver is
disabled when the driver is enabled and is enabled when the driver is disabled. This prevents data from being echoed back into the RS-232
device. The RS-232 side has a DB-9 female connector. The RS-485 side has a six-position RJ11 connector.
Connections
Regardless of the system, the 485SD9RJ must be connected with the proper polarity (See Table 1). With no data being sent and the
driver enabled, the RS-232 line should be negative and the Data(A) should be negative with respect to Data(B).
Proper operation of any RS-485 system requires the presence of a signal return path between the signal grounds of the equipment at
each end of an interconnection. This circuit reference may be established by a third conductor connecting the common leads of devices, or it
may be provided by connections in each equipment to an earth reference. When the circuit reference is provided by a third conductor, the
connection between the signal grounds and the third conductor should contain some resistance (e.g. 100 ohms) to limit circulating currents
when other ground connections are provided for safety.
Table 1: 485SD9RJ Pin-Outs
Specifications
Communication:
Two-wire
Data Rate:
115.2K Baud max.
Power:
Port-powered from handshake lines
Dimensions:
3.0"L x 1.3"W x 0.9"H
Temperature Range: 0
C to 70
C
DECLARATION OF CONFORMITY
Manufacturer's Name:
B&B Electronics Manufacturing Company
Manufacturer's Address:
P.O. Box 1040
707 Dayton Road
Ottawa, IL 61350 USA
Model Number:
485SD9RJ
Description:
RS-232 to Rs-485 Data Converter with
Send Data Control, Port-powered, DB9 to RJ45
Type:
Light industrial ITE equipment
Application of Council Directive: 89/336/EEC
Standards:
EN 50082-1 (IEC 801-2, IEC 801-3, IEC 801-4)
EN 50081-1 (EN 55022, IEC 1000-4-2)
EN 61000 (-4-2, -4-3, -4-4, -4-5, -4-6, -4-8, -4-11)
ENV 50204
EN 55024
Michael J. Fahrion, Director of Engineering
Signal
RJ11 Pin #
Data A (-)
2
Data B (+)
5
Signal Ground
4
Figure 1
RS-485
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