From my Visual Basic program I have been using the PORT95 utility (available for example from http://www.programmersheaven.com/zone2/cat490/2884.htm
)to access the PC parallel port by reading and writing registers $0378-$037A. Works fine!
The serial port is controlled by registers $03F8-$03FF. But these registers could not be accessed with PORT95! Reading the registers with PORT95 I always get $FF what obviously is wrong. For example $03FB-$03FF should be R/W but trying to modify one of these registers and then reading back, all with PORT95, I always get $FF.
How is this possible? If PORT95 cannot be used, how to access the serial port?