I try my best to translate the manual as the manual is originally written in Chinese language. The manual is too simple and not really provides the details.

serial port setting:
  • 1 start bit + 8 data bit + 1 stop bit, no parity
  • baud rate: 4800 baud
  • 5 bytes format, 60 packages per second, bit 7 is the synchronous bit

byte 1:
  • bit 7: synchronous bit, as 1
  • bit 6: 1=instruction for pulse sound
  • bit 5: 1=SpO2 decrease, 0=OK
  • bit 4: 1=searching time too long, 0=OK
  • bit 3-0: signal strength (0-8), represent signal strength of pulse

byte 2:
  • bit 7: synchronous bit, as 0
  • bit 6-0: pulse wave diagram

byte 3:
  • bit 7: synchronous bit, as 0
  • bit 6: pulse rate bit 7
  • bit 5: 1=search pulse, 0=OK
  • bit 4: 1=sensor error, 0=OK
  • bit 3-0: pulse bar diagram

byte 4:
  • bit 7: synchronous bit, as 0
  • bit 6-0: pulse rate, (bit 6 to bit 0)

byte 5:
  • bit 7: synchronous bit, as 0
  • bit 6-0: SpO2