Section 4: Theory of operation
Models 707B and 708B Switching Matrix Reference Manual
4-6
707B-901-01 Rev. B / January 2015
Upper crosspoint display (Model 707B only)
The larger upper display on the Model 707B mainframe provides a visual means of determining the
relay status of each card slot in the instrument at any given time. It also shows the label names for
each row and column of the given slot.
The crosspoint display may be operated from the navigation wheel to scroll through the slots
displaying the status. You can use the navigation wheel to select channels for relay open or
closures or other actions.
For details on indicators and additional options, see
Crosspoint display (Model 707B only)
Figure 80: Model 707B crosspoint display block diagram
Description of the crosspoint display components
The front panel of the Model 707B is composed of two main display components: a vacuum
fluorescent display (VFD) and a 12 x 12 LED matrix display, called the crosspoint display, that shows
the relay status for each of the slots.
The block diagram shows only the matrix display. Its constituent components are described below.
Microcontroller
The microcontroller receives commands from the main controller and updates the row and column
labels. It also generates the pulse-width modulated (PWM) signals for operating the 12 x 12 LED
matrix.