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Q28843: Why QuickBASIC Does Not Support COM3: and COM4: Serial Ports

Article: Q28843
Product(s): See article
Version(s): 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | B_BasicCom | mspl13_basic
Last Modified: 26-MAR-1990

Question:

Why doesn't QuickBASIC support the COM3: and COM4: data communications
ports?

Response:

Support for these two additional communications ports requires a
larger code size for QuickBASIC in both the compiler and the run-time
module. Therefore, the decision was made not to support COM3: and
COM4:.

The QuickBASIC compiler supports the use of serial communications
ports COM1: and COM2: through the use of the OPEN "COM" statement.
Information on how to access these ports can be found on Page 296 of
the BASIC language reference manual for the following products:

1. Microsoft QuickBASIC Versions 4.00 and 4.00b for MS-DOS

2. Microsoft BASIC Compiler Versions 6.00 and 6.00b for MS-DOS and
   MS OS/2

To access COM3: and COM4:, it may be possible for compiled BASIC to
call third-party library routines, which are listed in catalogs such
as the "Programmer's Connection Buyer's Guide" [in the United States,
call (800) 336-1166; in Canada, call (800) 225-1166; to reach Customer
Service, call (216) 494-8899]. For example, you may want to contact
the company Software Interphase at (401) 274-5465 to determine if
its product QuickComm supports COM3: and COM4: called from Microsoft
compiled BASIC.

For a list of other catalogs, search for the following words:

   programmer and tool and catalog

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