WARNING: Be very careful when following the procedure for adding ports. If an error is made, you may need to use the emergency repair disk to recover.
To configure multi-port serial adapters for Windows NT.
Add Value Names Data Type DataExit from Regedt32, and enter the following 2 commands to activate the changes:
ErrorControl REG_DWORD 1 Group REG_SZ Extended base Start REG_DWORD 2 Type REG_DWORD 1
The serial ports should now work. Restarting Windows NT will also activate the changes.
Note that COM1: through COM9: can be directly referenced just like a filename from programs and from the command line. However, COM10: and above must be referenced with the following syntax:
The command line MODE command does not recognize ports above COM9:.
Sample Configuration Key Values
The sample below assumes that there are two serial ports already available that will be listed as "Serial0" and "Serial1" in the Registry and assigned to COM1: and COM2: respectively. The additional ports will start at COM3:. For more than four port adapters, simply continue the pattern for as many ports as needed.
Example : Quadport 4-port adapter at IRQ10, starting port address 500, starting at COM3:.
You must program the Interrupt Pending Register for the Quadport at 0x0140 or another free range.
The IRQ Pending register will occupy 8 contiguous locations (ie. 0x0140..0x0147)
Serial0 = COM1 and Serial1 = COM2
Add Key Add Value Names Data Type Data (no class)Currently Windows NT supports up to 256 COM: ports although the command line MODE does not support over COM9:.
Serial2 PortAddress REG_DWORD 0x500 Interrupt REG_DWORD 0x0a DosDevices REG_SZ COM3 PortIndex REG_DWORD 1 InterruptStatus REG_DWORD 0x140 Serial3 PortAddress REG_DWORD 0x508 Interupt REG_DWORD 0x0a DosDevices REG_SZ COM4 PortIndex REG_DWORD 2 InterruptStatus REG_DWORD 0x140 Serial4 PortAddress REG_DWORD 0x510 Interrupt REG_DWORD 0x0a DosDevices REG_SZ COM5 PortIndex REG_DWORD 3 InterruptStatus REG_DWORD 0x140 Serial5 PortAddress REG_DWORD 0x518 Interupt REG_DWORD 0x0a DosDevices REG_SZ COM6 PortIndex REG_DWORD 4 InterruptStatus REG_DWORD 0x140 NOTE : You must activate the Quadport IRQ Pending register and apply that value in the above structure for the IRQ sharing feature to function.
This feature is available on any of the Quadport products using the latest control software.
Also ensure that the IRQ you are selecting is truly conflict free and not used by another ISA / PCI bus product.