What IR Protocol is this?
the protocol is chinese: the encoder IC is SW5104 by Swsem.com
Function Description

Key input terminals K1—K8
In static mode, the key input terminals K1~K8 are set to high level by the internal pull-up resistor, and in the circuit no current flows; when any key is pressed (that is, grounded), the corresponding programming will be generated.
User code coding bits C1 and C2
In static mode, C1 and C2 are also set to high level by internal pull-up resistors. Users can, if needs, to be set to four different user code combinations.
Data output
The generated code is output by the DOUT terminal, please refer to the data output format in the figure below.
The following parts are composed:

(1) Start code----1 1 0
(2) User code----C1 C2
(3) Instruction code-7-bit key code signal (for details, please refer to the BEC5104 key code table)

Encoding format

(1) &quot;0&quot;: 1/4T high level, 3/4T low level;  &quot;1&quot;: 3/4T high level, 1/4T Low level
(2) The period of each bit code T = 1.6879ms
(3) The interval between every two frame codes is 4T
When a key is pressed, the LED port outputs high level, after a delay of 32ms, the DOUT port opens. Begin outputting valid data codes. When the button is kept pressed and held, the coded signal will be output continuously. The time interval between each data frame is the length of the 4-bit data code.

Oscillator
The internal oscillator of the chip integrates an advanced button start-up power saving mode, when no button is pressed. When the oscillator is in sleep state, no current flows; when a key is pressed, the oscillator starts to work, which saves the power consumption of the system to the greatest extent. When using, it needs to be on the OSC1 and OSC2 ends connect a 455KHz crystal in parallel, please refer to the application circuit for details.
SW5104 Key code table


NOTE:  C1 and C2 are determined by the user. The corresponding bit is &quot;0&quot; if it is floating or grounding. If connected to VDD is &quot;1&quot;.
Features and applications

Features
•   SW5104 adopts 38KHz carrier code transmission, the output has good directionality, anti-interference features such as strong interference ability and long remote control distance.
•   SW5104 adopts the power-saving mode design of button start-up and low static power consumption.
•   SW5104 has 8 input channels and 2-digit user code setting keys, so it has 32 different combinations and can produce 32 different encoding outputs for users to choose.
•   CMOS process design
•   Wide working voltage range 2.0V~5.0V
•   Strong ESD resistance

Application
•   Can be used as a remote control for some household appliances and electric toys (for example, with BEC820XX series decoders are used together as remote control and receiver of electric fan)


•   Infrared remote control communication with MCU within a certain distance
Application circuit.
The following figure is a typical wiring diagram of SW5104 used as an electric fan remote control. When used for other purposes, on the way, according to specific requirements, refer to the wiring diagram to make appropriate adjustments.