CompuServe Thread

The problem is Windows, not the modem. The Windows communications drivers are buggy to say the most for them and they do not recognize COM3 and COM4. You may be able to overcome some of the Windows problems by installing the TubroCom replacement communications drivers for the Windows drivers. TubroCom can be reached at (510) 540-8080. TurboCom supports the 16550 UART and also enables COM3 and COM4. You are indeed correct that this is a 'serious problem' and it is unfortunately one which MicroSoft is responsible for and so far has done nothing to correct. Incidentally, you should NOT use the pointing device and the internal modem on any combination of ports which share the same interrupt. (IRQ3 is shared by COM2 and COM4 while IRQ4 is shared by COM1 and COM3. This is a function of DOS, not of Windows or the modem.) With your mouse on COM1 you would want the internal modem as either COM2 or COM4, as you currently have it. But, this assumes that Windows will support COM4 which it does not. There are some 'work-arounds' which can be done with base address changes in the SYSTEM.INI file. You may be able to find information on this in the Windows forum. But, as I recall these changes only work for the STANDARD mode and not for 386/E mode in Windows.