User`s manual

DIGITAL-LOGIC AG MSLB-P5 Manual V0.3
PRELIMINARY 37
4.3.4 Serial Ports COM1-COM4 RS232C
Select the RS232C Interface with:
J108: 2-3 Select COM3 = RS232C
J109: 2-3 Select COM4 = RS232C
J115: 2-3 Select COM3 = IRQ10 (1-2 = IRQ4 *)
J114: 2-3 Select COM4 = IRQ11 (1-2 = IRQ3 *)
*) if IRQ3/4 used, the driver must handle the shared IRQ3/4 with the COM1/2 !
The serial channels are fully compatible with 16C550 UARTS. COM1 is the primary serial port, and is
supported by the board's ROM-BIOS as the PC-DOS 'COM1' device. The secondary serial port is
COM2; it is supported as the 'COM2' device.
Standard: COM 1/2: 16C550: 2 x 16C550 with 16 Byte FIFO
Serial Port Connectors - COM1, 2 generally
Pin Signal
Name
Function in/out DB25 Pin DB9 Pin
1 CD Data Carrier Detect in 8 1
2 DSR Data Set Ready in 6 6
3 RXD Receive Data in 3 2
4 RTS Request To Send out 4 7
5 TXD Transmit Data out 2 3
6 CTS Clear to Send in 5 8
7 DTR Data Terminal Ready out 20 4
8 RI Ring Indicator in 22 9
9 GND Signal Ground 7 5
The serial port signals are compatible with the RS232C specifications.