SYMEK FSK-9601, Руководство пользователя

Страница: 5 / 9

FSK 9601 Page 5
With this circuit, it is only possible to switch DC-voltages up to about 20 Volts to ground. You cannot pull a line up to 12 Volt
when transmitting or switch a negative voltage. For this application, you should use a switching amplifier or a reed relay (with
diode clamp).
At most (handy) radios, the PTT contact and microphone is connected to the same signal pin. The AF-path for the micro-
phone signal is decoupled by a series capacitor, the PTT-signal is fed by a series resistor of 2 to 20 k
Ω
in order not to short-
circuit the microphone. When pressing the PTT switch, DC current may flow through this resistor, keying the transmitter. As
the microphone will not be used with the 9600 Baud FSK-modem, the mic-connector of the radio may be connected directly to
the PTT-pin of the modem. Then, the short circuit of the mic-modulation is no disadvantage.
GND (Pin 2)
Ground of the radio (case, 0 Volt)
Standard FSK connection cable
for transceivers with 9600 Baud FSK Capability
Since about 1994, the industry begun to produce amateur radio transceivers with the necessary inputs and outputs for 9600
Baud FSK. The transceivers of Kenwood, Azden Alinco, Yaesu, ICOM, SYMEK use the same connector and pinning and are
easy to connect to a FSK9600. The radios have a 6 pin mini-DIN socket (same type as for PS/2 keyboards). You have to
make a simple cable with a 6 pin jack on the one side and the 5 pin DIN jack on the other. Just connect the pins 1 to 1, 2 to 2,
3 to 3 and 4 to 4. Pins 5 (and 6) remain unconnected. As it is difficult to solder the tiny 6 pin jack it is better to buy a ready-
made PS/2 keyboard extension cable, cut it into two pieces and attach the 5 pin DIN connector to the open end. Read the
manual of the radio, how the FSK mode is to be enabled and how to adjust sensitivity. If the demodulator output voltage
exceeds 0.5 volt, it is a good idea to reduce it to that level by soldering a voltage divider into the cable plug.
TRX4S, Kenwood, Yaesu, Azden etc.
TRX4S, TM733, TM455, TM251, TM451, TM-V7E, Azden PCS9600, Yaesu FT8500 etc. with 6 pin mini-DIN DATA-socket:
Modem Pin 1 (MOD) radio Pin 1 Data in, packet data input
Modem Pin 2 (GND) radio Pin 2 Ground
Modem Pin 3 (PTT) radio Pin 3 PTT, 'standby'
Modem Pin 4 (DEMOD) radio Pin 4 Data out, 9600 Baud packet output
TEKK KS960 Tnet Mini
9-pin sub-D plug (socket at the transceiver)
Modem Pin 1 (MOD) radio Pin 4 Transmit Data in
Modem Pin 2 (GND) radio Pin 2 Ground
Modem Pin 3 (PTT) radio Pin 3 PTT Line
Modem Pin 4 (DEMOD) radio Pin 5 Receive Data out
Reduce data out voltage via a 1:3 voltage divider (22 k
Ω
in series, 10 k
Ω
parallel) to 0,5 volt.
Settings and adjustments of modem FSK9601
Jumpers FSK9601
Note: the modem board is built-in in the TNC3 or TNC31 bottom-up (component side down). The following description shows
the modem board with the component side down! Jumper 1 is near the edge of the modem board, the jumper 4 is located with
4 to 5 mm distance to the modulation amplitude trimmer.
The jumpers are closed by normal 2,5 mm jumper bridges. Unused jumpers may be plugged parallel to the board edge on the
pins which are nearest to the board. All these pins are connected to ground.
„
= jumper installed
:
= no jumper
Normal mode: The modem is shipped with no jumpers active. The jumpers are plugged parallel to the board on the ground
pins.
(DIN-Connector) (Trimmer)
4 3 2 1
• • • •
• • • •
Normal mode: FSK
Bit-Error-Test (Jumper 1)
To run the bit-error-test ("BERT"), the transmitter is set to 'permanent zero' transmission. Check at the remote receiver, for
'ones': Every pair of 'ones' represents a transmission error. BERT is useful for test and adjustment of the signal path.
NOTE: if jumper 1 os closed, no ndata can be transmitted. However, the TNC may key up the transmitter and apparently data
is sent. But with BERT jumper installed, this data contains no information and no connect is possible.
(DIN-Connector) (Trimmer) 4 3 2 1
• • • •
• • • •
Bit-Error-Test mode enabled
Permanent transmit on PTT (jumper 2)
With jumper 2, the PTT of the radio may be keyed. This is used for tests and adjustment. The transmit time limiter (Watchdog)
is not in effect when keying the PTT by jumper 2. For normal operation, set jumper 2 always 'OFF'!
For testing, it makes sense to install jumper 1 (BERT) and jumper 2 (transmit) at the same time.