Anything I send from the co-ordinator arrives at the end device as expected.
Any response from the end device arrives at the Co-ordinator as expected UNLESS there is a gap of no data for 30 seconds.
In this case, data entered at the end device does not get sent for 15 seconds. Anything entered into the end device during that 15 seconds is lost.
So for example a command is sent from the co-ordinator to the end device. As long as the end device replies within 30 seconds, all is ok. If the end device takes longer than 30 seconds to reply, the reply is lost.