Digi XBee Product Manual page 91

Figure 16: AT Command frames
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Identifies the UART data frame for the host to
correlate with a subsequent ACK (acknowledgement).
If set to ' 0 ', no response is sent.
Figure 17: Example: API frames when reading the DL parameter value of the module.
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Figure 18: Example: API frames when modifying the DL parameter value of the module.
Byte 1
0x7E
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* Length [Bytes] = API Identifier + Frame ID + AT Command + Parameter Value
** "M" value was arbitrarily selected.
AT Command - queue parameter value
API identifier value: 0x09
This API type allows module parameters to be queried or set. In contrast to the "AT Command" API
type, new parameter values are queued and not applied until either the "AT Command" (0x08) API
type or the AC (Apply Changes) command is issued. Register queries (reading parameter values) are
returned immediately.
AT command response
API identifier value: 0x88
Response to previous command.
In response to an AT Command message, the module will send an AT Command Response message.
Some commands will send back multiple frames (for example, the ND (Node Discover) and AS (Active
Scan) commands). These commands will end by sending a frame with a status of ATCMD_OK and no
cmdData.
XBee / XBee-PRO RF Modules 802.15.4 Product Manual
Length
0x7E MSB LSB API-specific Structure
API Identifier
0x08
Frame ID (Byte 5)
Byte 1 Bytes 2-3
0x7E 0x00 0x04
Length*
* Length [Bytes] = API Identifier + Frame ID + AT Command
** "R" value was arbitrarily selected.
Bytes 2-3 Byte 4
0x00 0x08 0x08
Length* API Identifier
API Operation for the XBee/XBee-PRO RF Module
Frame Data Checksum
1 Byte
Identifier-specific Data
cmdData
AT Command (Bytes 6-7)
Command Name - Two If present, indicates the requested parameter
ASCII characters that value to set the given register .
identify the AT Command. If no characters present , register is queried.
Byte 4 Byte 5
0x08 0x52 (R)
API Identifier Frame ID**
Byte 5 Bytes 6-7
0x4D (M) 0x44 (D) 0x4C (L)
Frame ID** AT Command
Parameter Value (Byte(s) 8-n)
Bytes 6-7 Byte 8
0x44 (D) 0x4C (L) 0x15
AT Command Checksum
Bytes 8-11
0x00000FFF
Parameter Value
Byte 12
0x0C
Checksum
92