Icom IC-751A Instruction Manual page 24

5 - 4 RTTY TERMINAL UNIT
•USING A HIGH SPEED RELAY
•USING A LEVEL CONVERTER
•USING AN AFSK GENERATOR
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.
ACC SOCKET
AFSK receive signal
ACC Socket pin 4
LOOP CURRENT
POWER
SUPPL Y
• An RTTY Terminal Unit for AFSK operation can also be con-
nected easily.
NOTE: Sorne 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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