Service manual

A-1
APPENDIX (SERIAL PORT INTERFACE PROTOCOL)
A1 Introduction
A2 Enabling the Serial Port
A3 Connecting to the Serial Port
A4 Real-Time Print Out
A5 Nurse call
A1 INTRODUCTION
When connected to the serial port on the back of the NPB-190, a real-time
printout can be obtained. Data lines are printed at 2 second intervals. Column
headings will be printed after every 25 lines, or if one of the values in the
column heading changes. Changing an alarm limit, for example, would cause a
new column heading to be printed. Printouts include patient and device data. A
real-time printout cannot be obtained if the unit is operating on battery power.
The real-time printout is discussed in more detail in Paragraph A4.
A2 ENABLING THE SERIAL PORT
Real-time data is constantly being sent to the serial port of the NPB-190 when
the instrument is operating on AC power. To receive a real-time printout, see
Paragraph A3 for instructions to make the connection.
Menu Item 6 is used to change baud rate. Item 6 cannot be accessed when a
sensor cable is connected to the instrument. To access menu Item 6, press both
the Upper Alarm Limit and the Lower Alarm Limit buttons simultaneously for 3
seconds. Next, press the Upper Alarm Limit button until menu Item 6 is
displayed. The baud rate can then be selected by pressing the Adjust Up or
Adjust Down button until the desired baud rate is displayed. A baud rate of 9600
is selected as a default value. Other baud rates that can be selected are 2400 and
19200.
A3 CONNECTING TO THE SERIAL PORT
Data is transmitted in the RS-232 format. Only three lines are used; GND is the
ground, TxD represents the Transmit Data Line, and RxD is the Receive Data
Line. Data can be transmitted a maximum of 25 feet. The pin outs for the serial
port are listed in the chart below.
Table A-1: Serial Port Pin Outs
Pin Line
2RxD
3TxD
5,10 GND
11 Nurse call
1, 4, 6-9, 12-15 No Connection