Modes Modes of operation
XBee®/XBee-PRO SX RF Module User Guide
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string +++ (without Enter or Return) and another full second of silence, it knows to stop sending data
through and start accepting commands locally.
Note Do not press Return or Enter after typing +++ because it will interrupt the guard time silence
and prevent you from entering Command mode.
When you send the Command mode sequence, the device sends OK out the UART pin. The device may
delay sending the OK if it has not transmitted all of the serial data it received.
When the device is in Command mode, it listens for user input and is able to receive AT commands on
the UART. If CT time (default is 10 seconds) passes without any user input, the device drops out of
Command mode and returns to Receive mode.
You can customize the guard times and timeout in the device’s configuration settings. For information
on how to do this, see CC (Command Character), CT (Command Mode Timeout) and GT (Guard Times).
Troubleshooting
Failure to enter Command mode is commonly due to baud rate mismatch. Ensure that the baud rate
of the connection matches the baud rate of the device. By default, the BR parameter = 3 (9600 b/s).
There are two alternative ways to enter Command mode:
Both of these methods temporarily set the device's baud rate to 9600 and return an OK on the UART
to indicate that Command mode is active. When Command mode exits, the device returns to normal
operation at the baud rate the BR parameter is set to.
Send AT commands
Once the device enters Command mode, use the syntax in the following figure to send AT commands.
Every AT command starts with the letters AT, which stands for "attention." The AT is followed by two
characters that indicate which command is being issued, then by some optional configuration values.
To read a parameter value stored in the device’s register, omit the parameter field.
The preceding example changes the device's destination address (Low) to 0x1F.
Multiple AT commands
You can send multiple AT commands at a time when they are separated by a comma in Command
mode; for example, ATSH,SL.
Parameter format
Refer to the list of AT commands for the format of individual AT command parameters. Valid formats
for hexidecimal values include with or without a leading 0x for example FFFF or 0xFFFF.
Response to AT commands
When reading parameters, the device returns the current parameter value instead of an OK message.
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