References of Load Communication Interfaces
 
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and a adapter with DB-25 plug (one end) and DB-9 plug (the other end) are 
required (not the modulating cable of the air-conditioner). 
 
 
RS232 Pins of Plug 
number 
Description 
1  No conjunction 
2 
TXD, data transmission 
3 
RXD, data receiving 
4  No conjunction 
5 
GND, grounding 
6  No conjunction 
7 
CTS, clear to send 
8 
RTS, request to send 
9  No conjunction 
 
RS-232 troubleshooting:   
In case of connection failure of RS-232, perform following check: 
  Check if the computer and load are provided with same Baud rate, parity 
check bit, data bit and flow control. The power shall be configured with one 
start bit (fixed) and one stop bit (fixed). 
  Just as described in the RS-232 connector, correct  interface cable or 
adapter shall be adopted. Note: even if the cable is equipped with right plug, 
internal wiring may be incorrect. 
  The interface cable must be connected to the correct serial port (COM1, 
COM2, etc.) of the computer. 
Setting of communication 
Before communication operation, be sure to match load and PC parameters (as 
follows). 
Baud rate: 9600  (4800/9600/19200/38400/57600/15200). You may enter 
system menu through the board to set communication Baud rate. 
Data bit: 8 bits 
Stop bit: 1 bit 
Check: (none, even, odd) 
EVEN All    all 8 data bits have even-parity check 
ODD All   all 8 data bits have odd-parity check 
NONE All    all 8 data bits have no check 
Local address: (0-31, factory set value: 0) 
Start Bit  Parity=None  8 Data Bits  Stop Bit 
 
5.2 USB Interface 
Connect the load and the computer using a cable with two USB interfaces