Lock Release - Icom IC-701 Instruction Manual

3-5 GROUND
In order to prevent electrical shocks, TVI, BC! and other
problems, be sure to connect a heavy wire ground, as
short as possible, from a good earth point to the ground
terminal on the rear panel.
3-6 MICROPHONE
The microphone supplied with the IC-701 is the IC-SM2
which contains a pre-amplifier. It's circuit diagram is shown
below. The IC-SM2 is an Electret Condenser type
microphone.
Schematic diagram of IC-SM2
R7 200M
(2)
°
3 3 7] °
o
°
TR1, TR2: 2SC536 or equivalent
A sensitivity contro! is installed on the bottom side of the
mic stand. By turning it in the "'H" or "L" direction, the
sensitivity will increase or decrease respectively. Adjust the
control so as to get the proper sensitivity considering the
distance to the mic, the loudness of your voice and the
environmental conditions. The wind screen not only
prevents background noise due to wind, but also protects
the mic. Unless required, do not remove the screen from
the mic. In order to operate the microphone, connect its
plug to the mic socket on the IC-701. To transmit, press
the PTT switch downward. When it is released, the IC-701
will return to the receive condition. For a long transmis-
sion, pull the PTT switch back while pressing it down until
the switch is locked and it will remain in that position until
it is pushed forward and released.
LOCK RELEASE
Key Wiring Diagram
If you would like to use a different microphone in your
car, an optional hand held dynamic microphone is available.
If other types of microphones are used, be sure their
impedance is between 500-600 ohms, and connect a 4 pin
plug in the manner shown.
Microphone plug exploded view
Microphone connection
Microphone
(cord side view)
3-7 CW KEY
When operating CW, connect the Key to the Key Jack with
the plug supplied. The connection of the plug is shown
below.
If the terminals have polarity, be sure to make the correct
connection.
Note that the keyed voltage when switching
with semiconductors or relays with resistors in the circuit,
should be adjusted to be below 0.4 Volts!
3-8 RTTY
When operating RTTY, connect the ACC socket pins 8
(ground) and 9 to your tele-typewriter through a high speed
relay or a level converter to TTL level, and the tones for
your terminal unit will be available from pin 4. For details,
refer to "How to use RTTY", and "Transmit and Receive"'
sections in this manual.