Visual Basic: MSComm Control

Visual Studio 6.0

CDHolding Property

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:

Part Description
object An object expression that evaluates to an object in the Applies To list.


The settings for the CDHolding property are:

Setting Description
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).

Data Type