INTRO
3
again, the changes will not be remembered unless you have used the PERM command, or using a
Battery Backup or SmartWatch.
All commands are listed alphabetically in the Commands Manual and many are discussed by mode
in this Operations Manual. The Command Manual also has an introduction that goes into more de-
tail on the structure of commands.
Asynchronous Commands
Asynchronous commands are commands that allow your TNC and computer to talk the same lan-
guage. These commands in the TNC will have their counterparts in your computer program,
although some programs may limit what you can set. Following is a list of TNC defaults and their
corresponding computer setting. then we will explain the commands using both the computer and
the TNC terminology.
TNC
Computer
ABAUD 0
The TNC runs an autobaud routine to allow it to match the
speed set in your computer when the TNC receives an asterisk
8BITCONV ON Data Bits or Word Length 8
PARITY 4
Parity no or none
ECHO ON
Full Duplex
XFLOW ON
Software Flow Control
Baud Rate
is how fast the computer and TNC will talk to each other. This is set in the TNC with
the ABAUD command. The settings allowed by the TNC are 0, 300, 600, 1200, 1800, 2400, 4800
and 9600. (
KPC-1
only allows 0, 300, 1200 and 9600.) When set to 0, the autobaud routine will
run at power-up – requiring you to press the asterisk whenever you turn on the TNC.
Word Length
and
Data Bits
are often used interchangeably to refer to how many bits are used
to recognize a character. Each character is made up of smaller parts called bits (analogous to a dit
or dah in Morse code). These bits are seen as high or low voltages on the cable between the TNC
and computer to make the desired combination for a character. A standard by the name of ASCII
allows 8 bits for each character, although all the standard alphanumeric characters and punctua-
tion can be recognized with only 7 bits. The TNC will talk to the computer using either 7 or 8 bits
depending on setting of the command 8BITCONV. As default 8BITCONV ON means 8 bits. Set
8BITCONV OFF to strip the 8th bit and use only 7 bits.
Parity
determines what the 8th bit will be and is an old form of error detection which few mod-
ern-day programs check. PARITY 4 is the default in the TNC which means the 8th bit will be seen
as part of the character. Odd or Even Parity will change the 8th bit depending on whether there is
an odd or even number of high voltages in the 7-bit character. Mark and Space Parity will hold the
8th bit either high or low. In the TNC, setting PARITY 0 is odd parity; Parity 1 is even parity;
PARITY 2 is mark parity; PARITY 3 is space parity and PARITY 4 is no parity. 8BITCONV must be
ON before the TNC will look at the 8th bit (the TNC always sends the 8th bit in TRANSPARENT
Mode).
Stop Bits
. The TNC always uses 1 stop bit.
Full Duplex
or
Half Duplex
. (Some programs use the term Echo for Half Duplex.) When using
Full Duplex the computer expects the attached device to send back (echo) what was sent to it. A
setting of Half Duplex will tell the program that it must do the displaying to the screen for what
you type. The TNCs default is ECHO ON, which tells the TNC to send back what it receives. This
