FRIENDCOM FC-302, Руководство пользователя

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Shenzhen Friendcom Technology Development Co., Ltd.
7
3.2 Interface for data transmission
As to FC-302 with internal modem, the pin definition is shown in Table 3.
Table 3
Pin Name Pin No. Decription Remark
AUDIO_IN
（
MOD IN
）
1
Audio input. 3Khz LPF, Modulation
sensitivity is 100mW
AUDIO_IN is effective only when PIN 7(MIC)
is vacant or with +5V high level. 3KHz LPF
filter existed in audio channel.
AUDIO_OUT
（ AF OUT ）
2
Audio output, 3Khz LPF. Output level at
60% frequency deviation is 100±30mV.
This line has an internal pull-up resistor
to +5V.
PTT
3
TX control
，
active low, only when PTT is
active AUDIO_IN and MIC IN are
effective. This line has an internal pull-up
to 5V.
GND
4
Ground
B+(9.6 ～ 16V
DC)
5
Positive pole input from DC power;
n12V
BUSY
6
Logical level output to indicated whether
there is a carrier or not. Low lever =
carrier , high level=no carrier. This line
has a pull-up to +5V. Also able to work as simulated serial and data
transmission port.
MIC IN
7
Microphones input. Can directly connect to electrets MIC, the DC
voltage of this pin should lower than 3.5V, then
MIC transmission can be activated.
SWITCH
8
Control output; 5V high level output
when active Also able to work as simulated serial and data
transmission port.
SPK
9
Audio output from the audio amplifier, @
8Ω AUDIO_IN is effective only when PIN 7(MIC)
is vacant or with +5V high level. 3KHz LPF
filter existed in audio channel.
GND
10
Power ground for modem
RXD
（
Modem
）
11
The serial data is input to modem through
this pin. Default is RS232. The hardware is one of RS232, RS485 or
TTL/5V when delivery.
EX_PTT
12
Data transmision control. Actice at low
level EX_PTT is valid with installed modems below:
FC-302-GMSK,
TXD
（ Modem ）
13
Serial data is output from modem via this
pin. Default is RS232. The hardware is one of RS232, RS485 or
TTL/5V when delivery.
CD_OUT
14
Logical level output to indicated whether
a carrier or not. Low lever = carrier , high
level=no carrier. Note: do not change the level to low unless the
internal modem needs.
NC
15
3.3 Modem Option for Data Communication
GMSK high speed modem are applied to the FC-302 data radio to increase capability for data
application. The goal of an internal modem is to improve the efficiency for data transmission and provide
maximum flexibility for user application.