Quatech HSU-200 사용자 설명서

See Figure 39 on the following page for a typical null modem cable. 

Figure 39 - Cabling requirements for RS-232C  devices 

 

RS-422/485 serial connections 

The Freedom USB-200/300 RS-422/485 adapters all come with standard 

female DB-9 connectors. The figure below shows the pin designations. 

Figure 40 - RS-422/485 DB-9 pin designations 

 

Freedom USB-200/300 serial USB adapters provide four differential 

communication signals (either RS-422 or RS-485) per channel. 

Transmit Data (TxD) and Auxiliary Output (AuxOut) are the two 
output signals. Receive Data (RxD) and Auxiliary Input (AuxIn) are 

the two input signals. The adapters also provide a ground signal. 
The AuxOut pair can carry the UART’s RTS signal. The AuxIn pair 
can carry the UART’s CTS signal. Alternatively, the AuxOut pair can 

be configured to internally loopback to the AuxIn pair, with the 
UART’s RTS signal also looped back to its CTS signal.  The following 

table shows the RS-422/485 connector definitions. 

Table 4 - RS-422/485 DB-9 signal definitions 

All ports

RS-422/485 signal description 

DB-9 

Auxiliary Output (AuxOut+) 1 
Transmit Data (TxD+) 

2 

Signal Ground 

3 

Receive Data (RxD+) 

4 

Auxiliary Input (AuxIn+) 

5 

Auxiliary Output (AuxOut–)  6 
Transmit Data (TxD–) 

7 

Receive Data (RxD–) 

8