Kantronics KPC-4 - Page 25

J
Hardware
Flow
Control
Hardware
flow
control
monitors
the
voltages
on
the
RTS
and
CTS
pins
of
the
RS-232
cable.
Therefore
these
two
wires
must
be
in
the
cable
between
your
TNC
and
computer.
The
TNC
holds
CTS
high
as
long
as
it
can
receive
data.
Once
its
buffer
gets
full
it
pulls
this
line
low.
The
computer
program
monitors
this
line
and
when
it
is
pulled
low
knows
to
stop
sending
data.
When
the
line
is
again
pulled
high
by
the
TNC
the
computer
program
will
restart
sending
data.
On
the
other
hand
the
computer
holds
RTS
high
as
long
as
it
can
receive
data
and
pulls
it
low
to
tell
the
TNC
to
stop
sending
data.
The
TNC
always
uses
hardware
flow
control,
so
only
wire
the
RTS
and
CTS
pins
if
your
computer
program
is
also
using
hardware
flow
control.
Convers
Mode
vs.
Transparent
Mode
In
the
Convers
Mode
there
are
many
special
characters.
To
list
a
few:
Command
Default
Description
SENDPAC
Ctrl-M
Causes
a
packet
to
be
packetized
DELETE
Ctrl-H
Backspace
character
REDISPLAY
Ctrl-R
Redisplays
the
keyboard
buffer
CANLINE
Ctrl-X
Cancels
a
line
STOP
Ctrl-S
Stops
output
from
TNC
to
computer
PASS
Ctrl-V
Pass
a
special
character
These
characters
are
all
very
useful
when
having
a
packet
conversation
with
someone.
If
you
want
to
send
a
packet
you
hit
the
return.
If
you
make
a
mistake
you
can
backup
with
the
delete
or
backspace
key,
or
kill
the
whole
line
with
Ctrl-X.
And
if
you
really
want
to
send
one
of
these
characters
you
can
always
proceed
it
with
a
PASS
character.
Transparent
Mode
is
made
more
for
the
sending
of
files,
whether
they
be
ASCII
data
files
or
program
files.
The
special
characters
do
not
mean
anything
to
the
TNC,
they
are
just
characters
to
be
put
in
a
packet
and
sent
to
the
radio.
(XOFF,
XON,
STOP,
START
may
be
used
depending
on
the
settings
of
XFLOW,
TXFLOW
and
TRFLOW,
see
the
flow
control
section.)
ASENDPAC
character
will
not
cause
a
packet
to
be
packetized,
instead
this
is
controlled
by
a
timer
(PACTIME).
This
way
short
lines
do
not
make
short
packets,
therefore
less
overhead
and
more
efficient
use
of
the
frequency.
How
congested
the
frequency
is
should
be
kept
in
mind
when
setting
the
PACLEN
and
MAXFRAME
parameters.
Besides
ignoring
special
characters,
Transparent
Mode
also
ignores
the
settings
of
8BITCONV
and
PARITY.
The
TNC
acts
as
though
8BITCONV
is
ON
and
PARITY
is
4
(none),
so
be
sure
the
computers
on
both
ends
of
the
connection
are
set
the
same.
All
monitor
commands
are
treated
as
OFF
in
Transparent
Mode.
All
you
will
see
is
what
is
being
sent
to
you.
You
would
probably
want
to
set
USERS
to
1
so
no
one
interferes
with
the
transfer.
The
setting
of
ECHO
is
also
ignored.
Even
if
ECHO
is
ON
Transparent
Mode
will
not
echo
to
the
attached
terminal.
Some
programs
allow
for
local
echoing
to
the
screen
while
uploading.
© Copyright 1989, Kantronics, Inc. All Rights Reserved. > :
Duplication
of
this
manual
or
the
firmware
without
Version
2.85
permission
of
Kantronics,
Inc.
is
prohibited.
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