DEC VT220 - Chapter 8: Monitor Circuits; 8.1 General

CHAPTER 8
MONITOR CIRCUITS
8.1 GENERAL
The monitor circuits and CRT (shaded areas of Figure 8-1), along
with the yoke assembly, are responsible for actual display to the
VT220 operator. The monitor circuits, located on the PS and
monitor board, develop the drive potentials for both the CRT and
the yoke assembly. The CRT generates an electron beam to provide
actual visual output; the yoke assembly controls the positioning
of the electron beam generated by the CRT.
COMPOSiTE
ViJ~O
MONITOR
ASSEMBl Y
EIA PRINTER 20mA
HOST PORT PORT
PORT
ViDEO
I LOGiC
____ ...1 _
SYSTEM
COMMUNICATION
LOGIC LOGIC
BOARD
'CO',NECTOR PHYSICALL Y 'flOUNTED ON
PS A\D MONiTOR BOARD
Figure 8-1 VT220 Series Terminal
Functional Block Diagram
8-1