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+HaierProtocol
+=============
+
+This library implements a Haier protocol transport level. It can help
+with sending and receiving messages to appliances that support it and
+process answers.
+
+Protocol description
+--------------------
+
+Haier protocol is a synchronous protocol. All data delivered with this
+protocol is split into portions - frames. The protocol has two versions.
+One is used for older HVAC units that work with the SmartAir2
+application. Another is for newer units that work with the hOn
+application. Those version commands are different but the frame
+structure and transport level of the protocol are the same.
+
+Haier frame
+-----------
+
+.. list-table:: Frame structure
+
+  * - **Frame separator**
+    - **Frame length**
+    - **Frame flags**
+    - **Reserved space**
+    - **Type**
+    - **Frame data**
+    - **Checksum**
+    - **CRC**
+  * - 2 bytes
+    - 1 byte
+    - 1 byte
+    - 5 bytes
+    - 1 byte
+    - | n bytes
+      | (n <= 246)
+    - 1 byte
+    - 2 bytes 
+
+Where:
+ * **Frame separator** - 2 bytes, have fixed value 0xFF 0xFF, used as a marker for the beginning of the frame
+ * **Frame length** - 1 byte, number of bytes of the entire frame, includes frame flags, reserved space, type byte, frame data, and checksum, max value is 254 \*
+ * **Frame flags** - 1 byte, only 2 values used 0x40 - indicates that frame have CRC bytes, 0x00 - indicates that there is no CRC
+ * **Reserved space** - 5 bytes, reserved for future use, filled with 0x00
+ * **Frame type** - 1 byte, type of frame (depend on the protocol)
+ * **Frame data** - n byte, data of the frame, can be empty. Sometimes first 2 bytes of data are used as a subcommand. Max size 246
+ * **Checksum** - 1 byte, the least significant byte of the sum of all bytes of the frame except separator bytes, CRC, and checksum itself.
+ * **CRC** - 2 bytes, CRC 16 of all bytes of the frame except separator bytes and CRC itself (Modbus CRC algorithm used). CRC is available only if the frame flags byte indicates it.