Keysight U1401B Guide De Démarrage Rapide page 12

Percentage scale of DC mA measurement
With the rotary switch at , another option
mA
selectable with the key is the percentage
scale of DC mA measurement.
Frequency measurement
During AC/DC voltage or AC/DC current
measurement, you can measure the signal
frequency by pressing at any time.
12 Keysight U1401B Quick Start Guide