An XBee device in Transparent mode simply passes information along exactly as it receives it. So, what you send is what other devices get. But sometimes you want to talk directly to the local device without sending data. For example, you may need to modify its configuration or alter the way it behaves. In that case, the XBee device needs to know that this communication should not be transmitted wirelessly.
Command mode is a state in which incoming characters are interpreted as commands. To get a device to switch into this mode, you must issue a unique string of text in a special way: +++. When the device sees a full second of silence in the data stream followed by the string +++ (without Enter or Return) and another full second of silence, it knows to stop sending data through and start accepting commands locally.
|Guard time silence||Command sequence||Guard time silence|
|One second before||+++||One second after|
Do not press Return or Enter after typing the +++ because it will interrupt the guard time silence and prevent the module from entering Command mode.
Once the device is in Command mode, it listens for user input for a while. If 10 seconds go by without any user input, the device automatically drops out of Command mode and returns to Transparent mode.