User`s manual

Input Characteristics
The multimeter is a floating, balanced differential multimeter. Floating means
the multimeter’s input terminals are isolated from its chassis. A balanced
differential multimeter is one where the input impedance between HI and COM
is the same as the impedance between LO and COM (see Figure 2-6). The
only difference between the HI and LO terminals is the polarity.
Figure 2-6. A Floating, Balanced Differential Multimeter
28 Configuring the HP E1326B/E1411B Multimeter Chapter 2