Technical Manual
FT420
– Iss 2.4
20
2.3 Main Display Driver Board SUB881
The FT420 Main Display comprises 2 subassemblies,
•
The Main Display Driver board SUB881 and
•
The Main Front Display board SUB882.
The Main Front Display board SUB882 contains the LED indicators and momentary push-button
switches. The SUB881 contains all the driving circuits to drive the LEDs and implement the switch
inputs. It also communicates with SUB880 via its own local microcontroller. The Main Display Driver
board layout is shown in Figure 3.
Figure 3 Main Display Diver Board Layout (SUB881)
The Main Display Driver board jumper settings and connections are shown on Table 7 and Table 8
respectively.
Table 7 Main Display Driver Board Jumper Settings
Designator
Description
Jumper
Status
Function
Factory
Default
JP1
Microprocessor
reset
ON
Set the system into reset state
OFF
Release reset for normal operations
Default
JP2
Mic type selection
Dynamic
Sets optional dynamic microphone
Electrets
Standard system electrets microphone
Default