Documentation

COM ports enumeration

Some people try to obtain a list of installed COM ports by looking in the "COM & LPT ports" key in the device manager, or by peeking in miscellaneous registry keys. However, depending on the provider, COM ports may be installed under other keys.

• To reliably enumerate COM ports, open each possible name (\\.\COM1 up to \\.\COM256) in its turn, and check a successful return from the Win32 function GetCommConfig, to confirm that it is really a COM port.
• You can also list and the key named "HARDWARE\DEVICEMAP\SERIALCOM" in the registry hive "HKEY_LOCAL_MACHINE" . It contains references to all installed COM ports. However there is no guaranties that this will be the case in future Microsoft operating systems.

In VIP version 3.0.x, the virtual ports are named "ELTIMA Virtual Serial Port..." in the "COM & LPT ports" section of the device manager. This will change in the next release.

Serial flow smoothness

This is caused by the constraints of packing serial data from the application into network packets as large as possible, while not introducing large delays between characters delivery.

There are some configuration possibilities to work around this.

• Uncheck the "strict baud rate" ("vitesse limitee") in the configuration options for the port.
• use RAW mode, and set the application to use a much greater baud rate than the one used. Set the real baud rate, flow control and data format directly in the port server.

Port server failure detection

In the special case where a port is used only for reception, and the port server reboots unexpectedly, the VIP service has no way to detect this event and won't try to reconnect.

This is true even if the reconnect option is ON both in VIPconfig and in the port server.