Service manual

Service Manual SD170E Series
Page 31 of 44
Channel Selection
Setting of channel selector switch for each channel
ACC-513 (GMSK Modem option board)
Connector
No.
Pin
No.
Function
Description
Input/
Output
Connector
1
1
VCC
6V to 12V Power Input
I/P
2
GND
Ground
3
PTT
Signal from the digital board to enable transmitter
circuit of modem board.
I/P
4
TXD_EN
It ensures that the radio has stabilized in
transmission before the data is processed for
modulation.
I/P
5
TX_END
To finish transmission, it indicates memory buffer
of Master MCU of digital board is empty.
O/P
6
MUTE
(Busy)
Logic level input from digital board to indicate
whether a carrier is present or not
I/P
7
MODEM_EN
Modem Enable input
I/P
8
POWER_SAVE
Power save input for modem board.
I/P
9
CMD_EN
It indicates that command for Modem
programming is effective.
I/P