26
Communications
Communications
Serial Output
The Model 2500A VET provides 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 in table 6.
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 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.
Real-time data may be printed or displayed by devices other than the pulse oximeter. On power up,
a header is sent identifying the format and the time and date. Thereafter, the data are sent once per
second in the following format:
SPO2=XXX HR=YYY
Where “XXX” represents the SpO
2
value and “YYY” represents the pulse rate. The SpO
2
and pulse
rate display as “---” if there are no data available for the data reading.
Table 6: 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
