Instructions

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Espressif Systems
ESP8266
AT Instruction Set
7.
AT+CIPSENDBUF – Write data into TCP-send-buffer
This command only writes data into TCP-send-buffer, so it can be called continually, and the user need
not wait for "SEND OK"; if a TCP segment is sent successfully, it will return <segment ID>, SEND OK.
Before data <length> is met, input "+++" can switch back from data mode to command mode, and
discard the data received before, cancel the "AT+CIPSENDBUF". This command can NOT be used on
SSL connections.!
AT+CIPSENDBUF – Write data into TCP-send-buffer
Single connection
(+CIPMUX=0)
AT+CIPSENDBUF=<length>
Multiple connection
(+CIPMUX=1)
AT+CIPSENDBUF=<link ID>, <length>
Response
<current segment ID>, <segment ID of which sent successfully>
OK
>
Wrap return ">" begins receiving serial data, when data <length> is met,
sends it; data more than <length> will be discarded, and returns "busy"
If connection cannot be established, or if it is not a TCP connection, or if
buffer is full, or some other error occurred, returns
ERROR
If data is transmitted successfully,
(1) for single connection, returns
<segment ID>, SEND OK
(2) for multiple connection, returns
<link ID>, <segment ID>, SEND OK
Parameters
<link ID> ID of the connection (0~4), for multi-connect
<segment ID> uint32, starts from 1, add 1 every time be called;
<length> data length, data more than <length> will be discarded, MAX 2048
bytes
Espressif Systems  / Friday, July 15, 201661 73