FT638 – Digital Radio Box
6.Mainb oard configuraton
6. Mainboard configuration
6.1.
RS232 levels (connection of MRT1 + MRT2)
Ex factory, a radio with a data communicaton
operatng on real RS232 levels is expected (e.g.
SRG3900, MTM800 FuG ET / MTM5500). If TTL levels
need to b e used (e.g. MTM800 FuG / MTM5200/5400
without COM connector), the following changes need
to b e performed:
MRT1: - move R143 to R142
- move R146 to R144
- remove R147
MRT2: - move R150 to R149
- move R152 to R151
- remove R148
6.2.
SQL configuration (connectors A1 + A2)
The SQL outputs can b e configured using JP1 A+B. Ex
factory, on incoming transmissions SQL switches to
+12V.
JP1 A for connector
A1
:
Pin 1+2 connected
SQL to +12V
Pin 2+3 connected
SQL to GND
JP1 B for connector
A2
:
Pin 4+5 connected
SQL to +12V
Pin 5+6 connected
SQL to GND
-11-
FT638_eng (29.04.22)
R148
R150 R149
R151
U4
R144
U1
D3
R147
C7
4H
C7
4G
C74E
C74F
C73E
C73F
C7
3G
C7
3H
R152
U16
R139
C99
C8
2
C8
3
C1
0
C19
C11
C20
C105
C107
C106
C104
R22
R9
6
R9
5
REL6
R1
02
R1
03
R1
04
R1
05
R1
07
R1
06
R1
08
R17
R14
R51
R49
R48
R53
U3
L1
C9
U21
R138
R56
REL5
R63
3
2
1
D5
3
2
1
D6
R141
R142
R62
R143
R146
REL2
REL1
U11
U12
C114
C113
1
U7
1
U8
C1
02
C3
5
C63
C6
1
C64
C6
0
C5
7
C5
8
C6
2
C5
9
C5
C1
7
C4
2
C103
C7
2
C7
1
C74
C73
C6
9
C6
7
C6
8
C7
0
R29
R4
7
R4
6
6 B
A
4
1
3
JP1
R3
4
C112
R52
R50
R4
2
R41
R1
37
R1
36
C115
8
1
ST2
8
1
ST12
8
1
ST1
