B&B Electronics 485SD9RJ Datasheet

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International Office: 707 Dayton Road PO Box 1040 Ottawa, IL 61350 USA 815-433-5100 Fax [phone]

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PRODUCT INFORMATION B&B ELECTRONICS

Model 485SD9RJ

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 55022

EN 61000-6-1
EN 61000 (-4-2, -4-3, -4-4, -4-5, -4-6, -4-8, -4-11)

Robert M. Paratore, Director of Engineering

Table 1: 485SD9RJ Pin-outs

Signal

RJ11 Pin #

Data A (-)

2

Data B (+)

5

Signal Ground

4

RS-485

Figure 1

485SD9RJ-0812-1/1

Signals From RS-232 Devices

Travel 4000 Feet on Phone Wires

Includes Send Data Control

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 piece of 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.

Specifications

Communication: Two-wire
Data Rate: 115.2K Baud max.
Power: Port-powered from handshake lines
Dimensions: 3.0L x 1.3W x 0.9H in
Temperature Range: 0 to 70°C