COM_DCD()
 Queries the Data Carrier Detect (DCD) status
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 Syntax

     COM_DCD(<nComPort>) --> lDCDActive

 Argument

     <nComPort>  Designates the port (1 to 4) on which DCD is tested.

 Returns

     A return of .T. indicates that DCD is active (MSR Bit 8 = 1).  A return
     of .F. indicates that DCD is inactive (MSR Bit 8 = 0).

 Description

     COM_DCD() lets you check the Data Carrier Detect signal within a
     program.  When you use a modem, DCD indicates that you have a remote
     connection.

 Note

     .  If Delta-DCD is required, you must use COM_MSR().

 Example

     A connection is only established when a valid DCD signal has been
     recognized:

     ? "Call recognized..."

     DO WHILE .NOT. COM_DCD(1)         // Wait for carrier (DCD)
        * ...
     ENDDO

     ? "Carrier recognized - connection established ..."