Dear All,
We use the VaComm component for a while to communicate with measurement devices plugged on COM port.
We successfully use it for direct COM port or even for redirected COM port on terminal server.
Recently, we encountered a problem for only one of our customer. He uses our application through Terminal server. So the COM Port are redirected through the RDP shortcut.
I created a simple app to reproduce the problem. Here is the process :
1. Connection to Terminal server with Port redirection activated.
2. on a CMD Prompt, execution of the following command : "change port /query" which list all the COM port recognised by the machine.
Result is :
AUX = \DosDevices\COM1
COM1 = \Device\RdpDrPort;COM1:1\tsclient\COM1
Which means that COM1 is the client COM port.
3. Test the communication on COM1 with a test application --> Communication OK
4. Test the COM1 opening whith the following application
VaComm1.Close;
VaComm1.PortNum:=1;
VaComm1.Baudrate:=br9600;
VaComm1.Databits:=db8;
VaComm1.Parity:=paNone;
VaComm1.StopBits:=sb1;
VaComm1.Buffers.ReadSize:=4096;
VaComm1.Buffers.WriteSize:=4096;
VaComm1.FlowControl.ControlDTR:=dtrDisabled;
VaComm1.FlowControl.ControlRts:=rtsDisabled;
VaComm1.FlowControl.DsrSensitivity:=False;
VaComm1.FlowControl.OutCtsFlow:=False;
VaComm1.FlowControl.OutDsrFlow:=False;
VaComm1.Open;
--> The communication doesn't work and the worst is that if I re-excute the command prompt, the COM1 redirection line disappeard. It looks like the action to open the VaComm1 connection make the COM Port redirection to crash.
I tested the same application directly on the client computer and the communication works so I don't think the problem is coming from the devices.
Doesn anybody have ever had this kind of problem? Or do you have any idea of what I could do to correct it?
Thanks a lot for your help.
Daniel Christe