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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: 

info@blackbox.com

  

 

 

Signal

 

DB-9 Female Pin #

 

TD 3 

RD 2 

RTS 7 
CTS 8 
DTR 4 

DSR 6 
DCD 1 

GND 5 

 Converter 
Terminal Block

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