Modem carrier detect

 BBS: Inland Empire Archive
Date: 02-01-93 (12:51)             Number: 368
From: CHARLES GRAHAM               Refer#: NONE
  To: JOHN KELLEY                   Recvd: NO  
Subj: Modem carrier detect           Conf: (2) Quik_Bas

> Looking for and example of code to monitor carrier detect.
> Would like to be able to have a local programer using
> Thorobred add carrier detect to his program but he has never
> seen any code as to what to do. I know there has to be
> someone in the Quick Basic world that can do this and
> hopefully we can transfer this to another basic program. Any
> help appreciated.

John - what you need to do is use QuickBASIC to read a byte
at the COM port and check the highest order bit of that
byte. If you're using COM1 the I/O port address is &H3FE.
For COM2 use &H2FE. Put a test like this in your main
communications loop:

                IF NOT INP(&H3FE) AND 128 THEN
                         'you ain't got no carrier
                END IF

Hope this helps...


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