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Q21789: No Support for More Than Two Communications Ports in BASIC

Article: Q21789
Product(s): See article
Version(s): 1.00 1.01 1.02 2.00 2.01 3.00 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | B_BasicCom | mspl13_basic
Last Modified: 26-MAR-1990

QuickBASIC does not support more than two communications ports.
QuickBASIC supports only the devices COM1 and COM2. Some computers
supply COM3 and COM4 devices, but these are not supported in compiled
BASIC. This information applies to Microsoft QuickBASIC Versions 1.00,
1.01, 1.02, 2.00, 2.01, 3.00, 4.00, 4.00b, and 4.50; to Microsoft
BASIC Compiler Versions 6.00 and 6.00b; and to Microsoft BASIC
Professional Development System (PDS) Version 7.00.

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," which can be obtained by
calling (800) 336-1166 in the United States; (800) 225-1166 in Canada;
or (216) 494-8899 for the Customer Service department. Using this
catalog, you may wish to contact the company Software Interphase at
401) 274-5465, for example, to determine if its product QuickComm
supports COM3 and COM4 called from Microsoft compiled BASIC.

When purchasing add-on products, make sure the vendor has tested its
product under your version of BASIC. For a list of other catalogs,
query on the following words:

   programmer and tool and catalog

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