SComm64 Communications DLL.



Retrieves the state of the Carier Detect (CD or DCD) liine.

Read Only at runtime.

MSComm32 and SComm64 have the same syntax and functionality


value = SComm64.CDHolding

value:- A Boolean Expression indicating the current state of the CD/DCD line.

If SComm1.CDHolding = True Then
   MessageBox.Show("DCD is On")
   MessageBox.Show("DCD is Off")
End If


The DCD line is a 'Modem Control' line. Not usually used when connecting two computers or other 'Terminal' equipment.

When using a Modem - your modem dials a number and negotiates a connection to a remote modem and this property will become true once the connection is established. Once this property becomes True it means that the modems have finished negotiating and you have a through connection to the remote computer and any data you send will be sent, via the modems, to the remote terminal.

If this property unexpectedly goes False during a modem connection then it means that your connection was lost.