I have an old Zenith 386sx laptop and wish to use the serial port for simulating a project I am working on. I am writing the simulator in QuickBasic and need to poke the port registers directly to increase the baud rate. QB only supports bauds up to 9600. The PC has a built in modem and only one serial port, which I can address as com1. Reading the bios addresses 0040:0000 thru 0040:0008 shows that the base address of the only port visible is in the slot normally used for com2 base address @ 0040:0002 & 3. This reads 02f8, the address normally used for com2. Reading the addresses @ 02f8 and just after yields all zeros. I suspect that this is not the correct address map for the port and/or the wrong address for the bios. Writing to com2 in QB does not stimulate the port pins. The machine boots into dos 6 and I don't run windows as it is a pain due to the port I need to use would normally support the mouse.
Question. What address is the bios location of the base address of com1 if not 0040:0000?
Question. What address is the bios location of the base address of com1 if not 0040:0000?