Brother HL-4200CN Service Manual page 303

1.3 Signal Name/Other description
Signal Name
Signal name configuration
REGI SENSOR
Part name
The above example indicates that the signal will be (L) when the registration
sensor detected a sheet of paper and that it will be (H) when the sensor has not
detected a sheet of paper and that the voltage is +5VDC.
1.4 DC Voltage
DC voltage is measured between each test point and the frame unless otherwise
instructed in Notes. The measured voltages are within the following ranges:
+3.3VDC (H)
(L)
+5VDC (H)
(L)
+24VDC (H)
(L)
1.5 Input/Output Test
DI: Digital input test
DO: Digital output test
Diagnostics on DI/DO can be executed on the Control Panel.
SENSED (L)
Active status Logical value
+3.1 to +3.5VDC
0.0 to +1.0VDC
+4.8 to +5.3VDC
0.0 to +1.0VDC
+23.0 to +25.2VDC
0.0 to +3.0VDC
VI-4
+5VDC
Highest level expected