15
Communications
Communications
Serial Output
Models 8500 and 8500M provide real-time data output capability via the pulse oximeter sensor
connector (a 9-pin Sub-D connector). The pulse oximeter sensor connector pin assignments
are listed below.
Information from the device, 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. The data are output at a rate of once per
second.
NOTE:
The 9th data bit is used for odd parity in memory download. In real-time mode, it is
always set to the mark condition. Therefore, real-time data may be read as 8 data bits, no
parity.
Real-time data may be printed or displayed by devices other than the pulse oximeter. At start
up a header is sent identifying the format and the date and time as HH:MM:SS, where “HH”
represents the hour, “MM” represents the minutes, and “SS” represents the seconds. The data
are sent once per second in the following format:
SPO
2
=XXX HR=YYY
where “XXX” represents the SpO
2
value, and “YYY” represents the pulse rate. The SpO
2
and
pulse rate will be displayed as “---” if no data is available.
Table 2: Pulse Oximeter Sensor Connector Pin Assignments
Pin Number
Assignment
1
1-Wire
®
2
Infrared Anode, Red Cathode
3
Infrared Cathode, Red Anode
4
Serial Data, TTL Levels
5
Detector Anode
6
Sensor Type
7
Cable Shield (Ground)
8
No Connection
9
Detector Cathode, +5 V