General IrDA Connections

The IrDA classes (IrDAClient, IrDAListener, etc) are quite similar to the Bluetooth ones. In IrDA, a service / application is identified by a textual Service Name. One can thus use code like the following.

This sample automatically chooses the (hopefully) single device in range.

Dim cli As New IrDAClient("MyCustomServiceName") 'Or "OBEX", "IrDA:IrCOMM" etc
...

Server side.

Dim lsnr As New IrDAListener("MyCustomServiceName")
lsnr.Start()
...

The DiscoverDevices method is present on IrDAClient too, but there is no equivalent to the SelectBluetoothDeviceDialog for IrDA currently.

The two connection modes IrCOMM and IrLMP (aka IrLPT) can be set by socket option. See the IrDAServiceClient samples or the samples on Alan’s website http://www.alanjmcf.me.uk/

On multiple dongles

Multiple dongles can be connected and Windows will use them all. An IrDAListener will listen on all — but it's not possible to tell which dongle the connection has been received over. It is also possible to connect back to another dongle on the same machine which can make testing a local server a bit easier. See e.g. http://32feet.codeplex.com/discussions/354693, http://msdn.microsoft.com/en-us/library/windows/desktop/ms691790(v=vs.85).aspx