Icom IC-751A - Rtty Terminal Unit

5-4
RTTY
TERMINAL UNIT
When operating
RTTY,
connect
the
ACC
CONNECTOR pin
9 and
pin
8
(ground) via a
high speed relay or through
a
level
converter for
conversion to
TTL level
to
your teletypewriter.
The audio tones for
your
terminal are
available from pin 4 and pin
8
(ground). The AF
output
level is about
300mVp-p for an
S9
signal.
•USING
A
HIGH SPEED
RELAY
•USING
A LEVEL CONVERTER
•
USING AN
AFSK
GENERATOR
•
An
RTTY Terminal
Unit for AFSK operation
can also be con-
nected
easily.
NOTE:
Some
RTTY Terminal
Units may require
the use
of
a
20dB audio preamplifier between pin
5 on the ACC
SOCKET
and the AFSK signal
output
from
the
Terminal
Unit to provide enough drive for full RF
output
power
from
the
transceiver.
The pin
5
input must be approxi-
mately 150mV
rms.
Check
your
RTTY
Terminal Unit Instruction Manual.
•
The AFSK signal may be connected
to
the
IC-751A front panel
MIC CONNECTOR pin
1
instead of the
ACC CONNECTOR if the
Terminal Unit
output
is not high enough.
An extra stage
of
amplification is provided in the
transceiver when using the micro-
phone connector.
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20
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