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1985-05-09
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120 lines
Description of TTY Program
TTY requires advanced basic 1.1, communications adapter,
and 80 character wide screen.
Comm adapter pins used are (2) xmit data, (3) rcv data, and (4) RTS.
RTS is active (plus) when the program is in transmit mode, and may
be used to control t/r switching in the TU or transceiver.
TTY transmits and receives 5 bit teleprinter code (murray/baudot)
at 45.45 baud (60 wpm) in half duplex mode and is intended for use
in the amateur radio service.
This documentation assumes the reader is familiar with amateur radio
teleprinter conventions and practices.
CAUTION: The IBM PC comm adapter uses rs 232 input and output voltage
levels of +12v/-12v. Most commercial TUs use TTL levels 0v/+5v.
Conversion circuitry may be required.
The TTY menu provides for selection of receive or transmit mode.
Switching between transmit and receive modes is done by calling the
menu, using the F10 key.
In receive mode, the normal mode of operation is to ignore incoming
cr and lf characters, and print full lines of 80 characters to the
display and printer. However, the F1 key may be used to select a mode
of operation in which cr/lf characters are recognized, and normal
teleprinter operation is simulated. F1 toggles this function on/off.
F2 toggles the PC line printer on/off.The printer is used in receive
mode only.
In receive mode, the program is arranged for "unshift" on space,
cr and lf, as well as "ltrs".
In transmit mode, ltrs and figs shift characters are inserted
where needed by the program.Ltrs and figs cannot be sent directly
from the keyboard. The ascii cr (enter) key sends a cr/lf/ltrs
sequence.The program assumes that the receiving terminal is
equipped with unshift on space, and inserts figs accordingly.
F3,F4,F6,and F7 are used to send preprogrammed messages. These
messages reside at lines 17000,18000, 20000,and 21000, and may
readily be changed to meet the needs of your station.
F5 sends the required Morse code station identifier. This subroutine
starts at line 19060. Morse code is sent by calling dit, dah, and
intercharacter space subroutines at 19500,19600,and 19700 in sequence.
Change lines 19060 thru 19080 to send your callsign.
The program will accept either upper case or lower case keyboard entry.
Other ascii characters which have no equivalent in murray code are
ignored.
Hints and Kinks:
The `ignore cr/lf' mode is very useful when receiving conditions are
less than perfect, and produces much more reliable copy. However,if the
chap on the other end wants to send you some teleprinter art, use the
cr/lf `on' mode.
If the other station is using a conventional teleprinter, his line
length is probably 70 or 72 characters. TTY lets you send 80 character
lines which will overprint at the other station. Be careful!
In transmit mode, characters appear on the screen when they are sent
to the output buffer. The screen may be up to 128 characters ahead of
the comm adapter output! F5 or F10 (cwid or return to menu) are stored
and do not take effect until the buffer is empty. Hence the program
may appear to `hang' while the buffer is emptying. Be patient! If it
didn't work this way, some of your deathless prose would be lost down
the bit bucket!
73 es GL de Bob Johnson AA4L, 11305 Rums Hill, Raleigh NC 27614
phone 919 847 5606
tty /murray Version 2.0 1/29/83
The program has been entirely rewritten to improve readability
and modularity. There are some significant functional changes:
`75 speed' and `100 speed' capability have been added. It is no longer
necessary to return to the menu to switch from receive to transmit and
vice-versa. The `CQ', `de', and `test' messages are still embedded in
the program code. However, in transmit mode, F1, F2, or F3 now cause
the program to read files named msg1, msg2, or msg3 from disk. These
files are then transmitted as text. This provides greater flexibility.
Version 1.0 outputted the cw id characters on the rs-232 transmit data
line. Due to some changes in station hardware at AA4L, cw id is now
keyed by means of the cassette tape motor control relay. Also, PC
generated sidetone is now audible through the system unit speaker.
It developed that Version 1.0 had a bug which could cause a system
crash. BASIC does not have provision to set the baud rate to 45.45.
Hence the speed change is accomplished by OUT commands to &h3f8 and
&h3f9. If a comm adapter interrupt occurs simultaneously with these
OUT instructions, a system crash can occur. This has been corrected in
Version 2.0 by the use of additional OUT instructions to disable the
comm adapter interrupts.
The embedded messages which you may wish to change to fit your station
are now at lines 16300, 16400, and 16500. The `dit' subroutine is at
18500, the `dah' at 18600, and the intercharacter space at 18700.
Change the gosubs following 18000 to call the dits, dahs and spaces
in the proper order to send your call. The msg1, msg2, and msg3 text
files are prepared using edlin or your text editor.
NOTE: In transmit mode, use the <\> (backslash) to send the tty
<BELL> character.
Version 2.1 - 02/05/83
A type-in message buffer has been added.
THERE ARE NO PROMPTS TO EXPLAIN THIS FEATURE DURING PROGRAM RUN!!
When the program is in "receive" mode, you may type into the
fifty line buffer. Be sure to end each line with a <cr>.
You may enter text into the buffer at the same time that characters
are being received from the comm adapter.
You cannot correct or edit what you have typed.
What you type will appear, line by line, on screen line 25,
replacing the receive mode prompts. After entering "transmit"
mode, you may transmit this buffer at any time by pressing key
<F9>.The buffer is effectively erased after transmission.
version 2.2 - 02/14/83
110 baud ascii capability has been added.
At the function menu, choice <4> will chain the program "asctty".
The protocols are 7 data bits, space parity, two stop bits.
GL de AA4L
9/29/83 -- Note that changes in the FCC regs have eliminated the
requirement for cw identification. You may wish to delete the CWID
routine, as it is no longer needed. This is easiest done by changing
line 16600 to GOTO 15080. Do this in both tty22.bas and asctty.bas.