Applies To:
  • CitectSCADA 1.00 1.01 1.10 1.11 1.20 2.00 2.01 3.00

The following is a description of the COMxI digiboard driver. 

The comxi driver support the DigiBoard COM4i serial communication board. The board memory address, I/O port address and interrupt number are set with jumpers on the board. The possible memory start addresses are 0xc000, 0xc800, 0xd000 and 0xd800. They use 32K of memory. The possible I/O ports numbers are 0x100, 0x110, 0x120, 0x200, 0x220, 0x300 and 0x320. The possible interrupt numbers are 2, 3, 4, 5, 6, 7, 10, 11, 12 and 15.
Boards form
Board name: User supplied unique name for the board.
Board type: COMXI
Address: 0xc800 Board's memory start segment (in hexadecimal)
I/O Port: 0x320 Board's Port number (in hexadecimal)
Interrupt: 5 Board's interrupt request line.
Special Opt: not used
Ports form
Port name: User supplied unique name for the port.
Port number 1 to 4
Board name: Use the Board name from the Boards form.
Baud rate: up to 115200 may be used
Data bits: 7 or 8
Stop bits: 1 or 2
Parity: 0, 1 or 2 (for none, odd and even parity)
Special Opt: -h Use DTR (data-terminal-ready) and RTS (request-to-send) signal for reception flow control, monitor CTS (clear-to-send) and DSR (data-set-ready) signal for output flow control.
-r Raise DTR only when transmitting.
-t Raise RTS only when transmitting.
-i String Dial modem string. This string is sent whenever the port is initialised. Special characters are
'~' delay for 500 milliseconds
'~{60}' delay for 30 (500*60) seconds.
'\M' send carriage return


  • XIBOOT.COM Software for loading comxi.fcm into the board
  • COMXI.FCM Driver for COMXI board
  • COMXI.DLL COMXI Driver for windows


  • Transmit buffer size 1600 bytes
  • Receive buffer size 1600 bytes
  • Maximum number of boards 4