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Using COM1 and COM2 (RS422)


I need more serial interfaces. How do I access COM2 ?


Check first if they are not already there. Go to services/Interfaces.

You see that dflex 1 is on address 200 and has interrupt 5. Address and interrupt are checked automatically by the program. Of course cards must be switched and jumpered so that no collision occurs.

Next step is to stop device driver that takes COM2 in Windows XP. Go to Settings/Control Panel/Administrative tools/Computer Management/Services & Applications/Services and Plug and Play. Set the startmode to disabled, Otherwise Windows will try to get the resource.

Then go to Device Manager, ports, and with right-mouse click disable the driver.

Boot the computer.

Then go to arguments.txt in D:\EditorGT\user\system and input –com2 if you want COM2 (in the rack version COM1 is the touch screen).

When you start next time the application. You will see COM2 in Services/Interfaces:


COM2 can be converted into RS422 by jumpering the CPU SBC860 card. For example below you see a connection to a Heidelberg ST400 machine.

COM2 (DB9 fem. connector) Heidelberg (DB9 male)

RxD+ (pin 3)                                      WHT (pin 2)

TxD+ (pin 2)                                       BRN (pin 3)

RxD- (pin 4)                                       GRN (pin 7)

TxD- (pin 1)                                       YEL (pin 8)

Motherboard CPU jumpers (COM2) default is RS232 not RS422:

JP2      2-3, 5-6, 8-9, 11-12 (RS422 printed on motherboard)

JP4      3-4 (RS422 printed on motherboard)

In Rapido:

  • Baudrate at 9600, 8 bits, odd parity, 1 stopbits, no handshake