Agilent Technologies N4413A User Manual page 23

Reference Impedance Indicators
An arbitrary reference impedance (non-50Ω) has been selected in Setup on at least
one port.
The data has been modified for a non-50Ω reference impedance on at least one port.
See "Setup > Test Port Impedance..." on page
NOTE If the default reference impedance value (50Ω) has been modified on at least
one port, the Port Impedance box shows the reference impedance values on all 4
ports.
Frequency Zooming Indicators
Frequency zooming or point skipping has been applied and a subsequent
measurement has been made, creating a new set of calibration data.
Frequency zooming or point skipping has been selected, but a subsequent
measurement has not been made.
See "How to Use Frequency Zoom" on page
Marker Indicators
Markers are turned on in the active state.
Markers are turned on in the fixed state.
See "How to Use Markers" on page
Chapter 2
120.
54.
50.
User Interface
The Main Screen
13