Timewave DSP-232, Operating Manual

Page: 146 / 271

Chapter 8 ASCII and Baudot Operation
Use this option when you’re typing into the transmit buffer and don’t want to be bothered worrying about line
length. You
shouldn’t use this option when retransmitting text received from another station; ARRL bulletins, for
example.
ALFRTTY has no effect in AMTOR; an LF is automatically added after each ( RETURN ).
AScii Immediate Command
Mode: Command Host: AS
ASCII
is an immediate command that switches your DSP into the ASCII mode.
ASCII is the proper mode to use if you want to use RTTY to transmit text, data or other information containing
lowercase and special characters not present in the Baudot/Murray and ITA #2 alphabets or character sets. When
8BITCONV is ON , 8-bit ASCII data may also be sent and received.
Because the ASCII character set requires a minimum of seven bits to define each character, under worst-case
conditions, ASCII is sometimes more subject to data errors and garbled text than Baudot/ITA#2 at the same data
rate.
ATxrtty
n Default: 0
Mode: Morse, Baudot and ASCII Host: At
“n”
0 to 250, signifying the length of time (in units of 100 mS) to delay before sending text.
ATXRTTY allows Morse, Baudot or ASCII characters to be transmitted automatically whenever they’re typed and
the TNC is in the Converse mode. When all the characters in the buffer have been sent, the DSP reverts to receive.
The number
n represents the length of time from the last character typed to the dropping of PTT. This feature makes
the repeated use of the commands
RCVE
and
XMIT
unnecessary.
AUdelay
n Default: 2 (20 msec.)
Mode: Baudot, ASCII, FEC, PTSEND, FAX and packet Host: AQ
“
n ” 0 - 120 specifies in units of 10 mS intervals, the delay between PTT going active and the start of the
transmit AFSK audio tones.
In some applications you may need to make a time delay from the moment the radio PTT line is keyed and the time
that audio is produced from the DSP. Most notably, on HF when an amplifier is used, arcing of the amplifier’s relay
contacts may occur if drive to the amplifier is applied before the contacts have closed. If arcing occurs, increase
AUDELAY
slowly until the arcing stops.
In VHF or UHF FM operation, some synthesized transceivers may produce undesirable spurious emissions if audio
and PTT are applied at the same time. These emissions may be reduced by setting
AUDELAY
to roughly half of
TXDELAY .
Please note that
AUDELAY must always be less than TXDELAY . It’s advisable that AUDELAY be set lower than
TXDELAY
by a setting of 10. For example, you’ve determined that
TXDELAY 20
works well for your transceiver.
Subtracting 10 from 20 yields 10, which is the recommended setting for AUDELAY . If a setting of AUDELAY 10
is too short, then set both
TXDELAY
and
AUDELAY
higher.
BAudot Immediate Command
Mode: Command Host: BA
BAUDOT
is an immediate command that switches the DSP into the Baudot mode.
8-8 September, 05