RTTY / ASCII
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AMTOR Mode by using the invert directive (Ctrl-C I). (See FSKINV for inverting for inverting signals
that you are transmitting.)
The LCRTTY command can be used to send and receive lower case RTTY. When ON, lower case
characters may be sent and receive in RTTY and AMTOR Modes of operation. This is accomplished
by using the RTTY NULL character as a special shift character. This method is also used in RTTY to
send the Russian Cyrillic alphabet. If USOS is ON, a received space will shift to lower case. The dis-
tant station will only receive lower case case characters if he also has LCRTTY ON.
The LOWTONES command controls the MARK and SPACE frequencies when using the standard
shifts of 170, 425 and 850 Hz. When ON, the European low tones are used, with MARK being
1275 Hz and Space being the MARK frequency plus the selected shift. When this commands is
OFF, the standard RTTY tones are used: MARK is 2125 Hz and SPACE is the 2125 plus the selected
shift.
The RBAUD command sets the baud rate to be used when entering the RTTY Mode from the cmd:
prompt with no speed specified. This setting is also used to set the baud rate when the Ctrl-C Ø
directive is issued.
The USOS command (Un-shift on Space) when ON will cause the KAM to switch from figures to
letters upon receiving a space character from the other end. If LCRTTY is also on, a received space
will switch to lower case characters.
When XMITECHO is turned on, the KAM will echo the transmitted characters to your terminal at
the time they are actually being transmitted. This can be useful for determining when your trans-
mit buffer is empty and therefore you may return to receive mode. With split screen programs, the
echoed data will show up in the receive window as it is echoed from the KAM.
Miscellaneous Information
Typically, in RTTY and ASCII operation, speed of transmission is specified in BAUD rather than
words-per-minute. A chart of comparison between these two is provided below:
BAUD WPM
45 60
50 67
57 75
75 100
100 132
110 147
150 200
200 267
300 400
You may set any desire baud rate, in 1 baud increments, from 20 baud up to a maximum of 500
baud. However, HF operation below 28 MHz is limited to 300 baud.
RTTY and ASCII signals are sent by transmitting two different tones, called MARK and SPACE. The
difference between these two signal frequencies is referred to as the SHIFT. Standard shifts em-
ployed in amateur RTTY communication are 170 Hz, 425 Hz and 850 Hz. The KAM supports all of
these shifts as pre-programmed shifts, but also support the selection of any desired shift through
the use of the SHIFT command. If this is set to MODEM, the
KAM will generate the MARK and
SPACE tones which are specified by MARK and SPACE commands. This would allow the use of non-
standard shifts or non-standard frequency pairs if desired.
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