IC1473A-F 703 p1 / 2
5852
Port Powered RS-232 to RS-422 Converter,
DB9F to Terminal Block
Product Code IC1473A-F
The unit is a port-powered two-channel RS-232 to RS-422 converter. It converts TD and RD RS-232
lines to balanced RS-422 signals. The converter can be powered from the RS-232 handshake lines, DTR
and RTS. If port-powering the unit, at least one of these handshake lines must be present, but can be in
any state. It can also be powered externally on the terminal blocks. The RS-422 driver and receiver are
always enabled.
To satisfy the requirements of some software packages, the RS-232 handshake lines are looped
back
(tied together). RTS is connected to CTS, and DTR is connected to DSR and DCD.
Connections
This model is configured to transmit both directions between an RS-232 and RS-422 system. The
RS-232 side is pinned out to connect directly into the COM port on your computer or any other DTE
device (Table 1). Connections to the RS-422 side of the converter are made through terminal blocks.
When connecting to an RS-422 system, the converter
must
be connected with the proper polarity as
shown in Figure 1. When no data is being sent and the driver enabled, the RS-232 line is negative and
the RS-422 line TD(A) is negative with respect to TD(B).
Table 1 - RS-232 Pin Out
Figure 1 - Connection to a RS-422 System
TD(B)+
RD(A)-
RD(B)+
GND
TD(A)-
GND
RD(A)-
TD(A)-
RD(B)+
TD(B)+
422PP9TB
terminal blocks
RS-422
Biasing Resistors
The biasing resistors for the RS-422/RS-485 receiver are 4.7k Ohm resistors. These resistors are
labeled R1 and R2 (See Figure 2).
Black Box Corporation - 1000 Park Drive - Lawrence, PA 15055-1018
Tech Support and Ordering: 724-746-5500 - Fax: 724-746-0746
To contact us about Black Box products or services:
Signal
DB-9 Female Pin #
TD 3
RD 2
RTS 7
CTS 8
DTR 4
DSR 6
DCD 1
GND 5
Converter
Terminal Block
