HP Codemaster 100 User Manual page 36

Operating Controls and Indicators
Control/Button
Lead Select
ECG Size
HR Alarm
ECG Output connector
1-8
Function
Selects an ECG source to monitor.
Changes the displayed ECG size.
Controls heart rate alarms.
Controls the volume of the QRS beeper.
Located on the right side of the unit - provides
analog 1V/mV output for external monitoring