42
SPECIALIZED COMMUNICATIONS
RADIO TELETYPE (RTTY)
RTTY is the data communications mode with the
longest history. It was originally designed for use with
mechanical teletypewriters which were often used
before personal computers became common. Now
you can easily start operating RTTY with a personal
computer and MCP. Unlike Packet, each time you
type a letter, it is transmitted over the air. What you
typed is transmitted and displayed on the computer
screen of the recipient.
RTTY operation uses frequency shift keying (FSK)
and the 5-bit Baudot code or the 7-bit ASCII code to
transmit information.
For the cable connections, refer to “RTTY
OPERATION” {page 77}.
For further information, consult reference books
about Amateur Radio.
1
Access Menu No. 41 and select an FSK shift.
•
FSK shift is the difference in frequencies
between a mark and a space.
•
The 170 Hz shift (default) is normally used on
the Amateur bands for the RTTY.
2
Access Menu No. 42 and select a key-down
polarity.
•
Select “oFF” (default) to transmit a mark when
keying down or “on” to transmit a space.
3
Access Menu No. 43 and select “2175” (high tone)
or “1275” (low tone) for mark.
•
High tone (default) is commonly used
nowadays.
4
Select an operating frequency.
5
Press
[MODE]
to select FSK mode {page 19}.
•
If necessary, access Menu No. 47 to configure
the appropriate audio output level for your
MCP. The audio output level of ANO
(
REMOTE
connector/ pin 5) changes
{page 78}. The
AF
control cannot be used to
adjust the audio level for your MCP.
6
Some stations may be operating in Reverse shift.
In this case, press
[MODE] (1 s)
to reverse the
shift (the upper sideband is used).
•
“FSR” appears.
•
Traditionally, the lower sideband is used for
FSK operation. Press
[MODE] (1 s)
again to
return to the lower sideband. “FSK” appears.
7
Follow the instructions provided with your MCP
and enter a command from your computer to
transmit.
•
The LED changes from green (RX) to red (TX).
8
Begin sending data from your computer.
•
Press
[PWR/ 4/ TX MONI] (1 s)
to monitor your
signals. Press
[PWR/ 4/ TX MONI] (1 s)
again
to quit this function.
9
When finished transmitting, enter a command from
your computer to return to reception mode.
•
The LED changes from red (TX) to green (RX).
The following frequencies (measured in kHz)
commonly used for RTTY operation:
a
d
a
n
a
C
/
.
A
.
S
.
U
1
n
o
i
g
e
R
U
R
A
)
a
c
i
r
f
A
/
e
p
o
r
u
E
(
0
4
8
1
~
0
0
8
1
2
4
8
1
~
8
3
8
1
)
0
9
5
3
:
X
D
(
5
4
6
3
~
5
0
6
3
0
2
6
3
~
0
8
5
3
)
0
4
0
7
:
X
D
(
0
0
1
7
~
0
8
0
7
5
4
0
7
~
5
3
0
7
0
5
1
0
1
~
0
4
1
0
1
0
5
1
0
1
~
0
4
1
0
1
5
.
9
9
0
4
1
~
0
7
0
4
1
5
.
9
9
0
4
1
~
0
8
0
4
1
0
1
1
8
1
~
0
0
1
8
1
9
0
1
8
1
~
1
0
1
8
1
0
0
1
1
2
~
0
7
0
1
2
0
2
1
1
2
~
0
8
0
1
2
0
3
9
4
2
~
0
2
9
4
2
9
2
9
4
2
~
0
2
9
2
2
0
5
1
8
2
~
0
7
0
8
2
0
5
1
8
2
~
0
5
0
8
2
Note:
The TS-480 transceiver utilizes the DSP IC to generate a
variety of the required audio tones for RTTY operation (AFSK).
