USR IOT USR-DR404 - Synchronous Band Rate (RFC2217); RFC2217 Protocol Description

USR-DR404 user manual www.usriot.com
Jinan USR IOT Technology Limited www.usriot.com
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3.4. Synchronous Band Rate (RFC2217)
Synchronous baud rate is named RFC2217. USR Similar RFC2217 make adjustments on the basis of RFC2217 protocol
to improve accuracy of transmission. Enable the baud rate function of WIFI serial server via AT command:
AT+AABR=on
This command takes effect immediately and does not need to be restarted. After restarting, the WIFI serial server will
restore the previous baud rate.
3.5. RFC2217 Protocol Description
Protocol length is 8 bytes. And values taken for example is in HEX:
Name
Packet Header
Baud Rate
Bits parameter
Parity
Bytes
3
3
1
1
Explanation
reduce
misjudgment
High is in front,
three bytes
represent a baud
rate value
data bit, stop bit,
parity
Remove 4 bits of
header and
ignore the high
bit
(115200,
N,8,1)
55 AA 55
01 C2 00
83
46
(9600,
N,8,1)
55 AA 55
00 25 80
83
28
Serial parameter bit:
Bit #
Explanation
Value
Description
1:0
Data bit selection
00
5 bits
01
6 bits
10
7 bits
11
8 bits
2
Stop Bit
00
1 bit
01
2bits
3
Parity Enable
00
Disable Parity
01
Enable Parity
5:4
Parity Type
00
ODD
01
EVEN
10
Mark
11
Clear
8:6
NC
000
0