MEDIAID 340V, User Manual, Page: 24 / 40

Operating the Model 340V
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3.8 Data Transmission
Serial and analog data can be transmitted through the DATA PORT
(FIG. 1) to a peripheral device.
Figure 1
Serial Data Transmission
Oxygen saturation data in the range
of 0-100% and pulse rate data in the
range of 0-250 BPM can be trans-
mitted to a serial port of a data
receiving device. The transmitted
data packet is comprised of data
bytes sent in the following order:
Status byte, %SpO
2
byte, Pulse Rate
byte, Temperature byte and
Checksum byte. The Status byte
contains flags as to the operational
state of the Model 340V:
Bit 7 : Not used.
Bit 6 : Pulse is lost,
having
previously
been
detected.
Bit 5 : Pulse detected, normal monitoring started.
Bit 4 : Error flag, indicating that an error is occurring.
Bit 3 to 0 : Number of bytes in the data packet.
The %SpO
2
byte contains the current oxygen saturation level. It is in 8-bit
binary format. The Pulse Rate byte contains the current pulse rate. It is
also in 8-bit binary format. The Temperature byte contains the current
temperature and is in 8-bit binary format. The range of numbers output
for temperature is 42 to 229. To convert the Temperature Byte to
temperature in degrees Celsius, add 200 to the 8-bit binary number and
divide the result by 10. For example, ([229 8-bit binary 200] /
10) ºC = 42.9 ºC. The Checksum byte is the complement of the lower
eight bits of the bytewise addition of status, SpO
2
, pulse rate and
temperature plus one. The data field is 8 bits, one stop bit and no parity.
Transmission speed is 9600 baud.