Visual Basic: MSComm Control
See Also Example Applies To
Determines whether the carrier is present by querying the state of the Carrier Detect (CD) line. Carrier Detect is a signal sent from a modem to the attached computer to indicate that the modem is online. This property is not available at design time and is read-only at run time.
The CDHolding property syntax has these parts:
|object||An object expression that evaluates to an object in the Applies To list.|
The settings for the CDHolding property are:
|True||Carrier Detect line is high|
|False||Carrier Detect line is low|
Note It is especially important to trap a loss of the carrier in a host application, such as a bulletin board, because the caller can hang up (drop the carrier) at any time.
The Carrier Detect is also known as the Receive Line Signal Detect (RLSD).