Printer/Serial Output; Table Iii: Printer/Sensor Interface Assignments - Respironics 920 Instruction And Service Manual

C. Printer/Serial Output
Both the 920 and 920M Hand Held Pulse Oximeters provide output
capability to a custom printer via the 9-pin Sub-D connector. This
connector serves as a sensor-input connector as well as a printer
interconnect device. The 9-pin Sub-D connector pin assignments
are listed in Table III.
Pin Number Assignment
1 Battery Voltage
2 Infrared Anode, Red Cathode
3 Infrared Cathode, Red Anode
4 Serial Data, TTL Levels
5 Detector Anode
6 Logic Level
7 Cable Shield
8 Coaxial Shield
9 Detector Cathode, +5 V

Table III: Printer/Sensor interface assignments.

The information from the 920 in the real-time mode is sent in an
ASCII serial format at 9600 baud with 9 data bits, 1 start bit, and 1
stop bit, odd parity. The data is output at a rate of once per second.
NOTE: The 9th data bit is used for parity in memory
playback mode. In real-time mode, it is always
set to the mark condition. Therefore the real-
time data may be read as 8 data bits, no parity.
The data printed by the 920P printer is in the following format:
HH:MM:SS SPO2=XXX HR=YYY
where "HH" represents the hour the real-time clock is set to, "MM"
represents the minutes, "SS" represents the seconds, "XXX"
represents the SpO value, and "YYY" represents the heart rate. The
2
SpO and heart rate will be displayed as "---" if there is no data
2
available for the data reading.
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