"Device Unavailable"; PS/2 SETUP Doesn't Recognize COM2 Port (43895)

SUMMARY

A "Device unavailable" error may occur when a QuickBasic program attempts to OPEN "COM2:" and the IBM PS/2 system SETUP utility hasn't been configured or can't be configured to recognize COM2.

This problem has been reported with the IBM PS/2 Model 30 computer. The SETUP utility doesn't make provisions for a second communications port. Therefore, the BIOS data area RS232_BASE does not contain the proper information that QuickBasic is looking for. A good example is an internal modem card configured as COM2 that is put in the PS/2 but not recognized as an actual communications port. QuickBasic looks in the BIOS data area to see if there is a COM2 port to use and doesn't find the proper information. This problem is caused by the PS/2 Model 30 (and possibly other models) and is not a problem with QuickBasic.

The RS232_BASE area can be set with the proper COM2 information using a simple QuickBasic program. This program can be found in this Knowledge Base by querying on the following words: This information applies to Microsoft QuickBasic Versions 4.00, 4.00b, and 4.50, Microsoft Basic Compiler Versions 6.00 and 6.00b, and Microsoft Basic PDS Version 7.00.