Devices using IrDA in the real world discover other devices by listening. You can configure how long the Java ME Platform SDK emulator waits to discover another device using the Discovery timeout field in the IrDA OBEX section of the preferences window. Enter a value in milliseconds.
At the API level, the discovery timeout value determines how long a call to Connector.open("irdaobex://discover...") blocks before it returns or throws an exception.
The maximum packet length affects how much data is sent in each packet between emulators. Shorter packet values result in more packets and more packet overhead.