Kantronics KPC-4 - Page 21

To
change
back
to
VHF,
I
would
enter
"la"
to
go
to
the
A
stream
of
VHF.
The
current
I/O
stream
when
the
TNC
is
first
turned
on
will
be
the
A
stream
of
the
port
specified
by
the
PORT
command
for
dual-port
units.
l
The
STATUS
command
allows
you
to
see
who
is
on
which
stream,
or
the
status
of
the
stream,
i.e.
waiting
acknowledgment,
connect
in
progress,
disconnected.
Turning
STATSHORT
ON
will
cause
the
STATUS
command
to
list
only
the
current
Input/Output
stream
and
any
connected
streams.
If
you
are
connected
and
have
MONITOR
and/or
MCON
OFF,
the
normal
headers
containing
the
"to"
and
"from"
callsigns
will
not
be
shown.
The
setting
of
STREAMEV
will
then
determine
how
often
you
see
the
stream
designator.
This
parameter
comes
defaulted
OFF,
so
the
stream
designators
are
only
shown
when
a
change
in
streams
occurs.
Turning
this
command
ON
will
make
the
stream
designators
show
on
every
packet.
Turning
STREAMCA
ON
will
also
add
the
callsign
of
the
"from"
station
beside
the
stream
designator.
Round
Table
Discussions
Several
people
talking
together
present
a
difficult
situation
for
packet
radio
since
the
protocol
requires
two
stations
to
connect
in
order
to
make
sure
they
receive
each
others'
packets.
If
you
wanted
to
be
absolutely
sure
that
everyone
got
everything
you
said
you
would
have
to
connect
to
each
person
and
retype
everything
to
each
person.
That
could
get
a
bit
cumbersome,
so
most
people
use
the
Unproto
Mode
and
are
aware
that
a
collision
may
occur
once
in
a
while.
You
can
usually
tell
by
the
conversation
if
something
was
missed;
if
you
don't
get
an
answer
to
a
question
it's
probably
not
that
he
is
ignoring
you,
but
either
the
question
or
the
answer
got
collided
with.
With
MONITOR
ON,
the
BUDLIST
and
BUDCALLS
commands
can
help
in
setting
up
your
monitoring
to
see
only
those
you
want
to
see.
List
up
to
10
calls
in
BUDCALLS
and
set
BUDLIST
to
BOTH.
Now
you
will
only
see
packets
"to"
and
"from"
those
calls.
If
you
like
you
may
each
want
to
connect
to
one
person,
then
you
know
at
least
that
one
got
what
was
said,
but
be
sure
MCON
and
MALL
are
ON.
Timing
Dwait vs. Persistence and Slottime
When
the
TNC
acts
as
a
digipeater,
packets
that
need
to
be
relayed
are
retransmitted
as
soon
as the
frequency
is clear.
Because
of
the
end-to-end
acknowledgment
of
these
kinds
of
packets
it is
best
for
an
originating
station
to
avoid
colliding
with
digipeated
packets.
The TNC
provides
two
ways
to accomplish
this delay.
These two methods
are
the
standard
DWAIT
method,
or
the
newer
PERSISTENCE/SLOTTIME
algorithm.
During
a
connect
using
no digis,
this delay
also
gives the
receiving
station
time
to
_ switch from transmit to receive.
Using the DWAIT method, once the TNC detects a clear frequency it will wait DWAIT
(times 10 milliseconds) time before beginning to keyup the radio to transmit a packet.
This is a packet originated by you not a digipeated packet.
The algorithm used with the PERSIST and SLOTTIME parameters helps avoid
collisions by randomizing the wait time before transmitting. The more random the
timing the less chance of two TNCs transmitting at the same time and colliding. Once
the TNC detects a clear frequency it will wait SLOTTIME (times 10 milliseconds).
Then it will generate a random number. If this number is smaller than the setting of
PACKET 15
©
Copyright
1989,
1990,
Kantronics,
Inc.
All
Rights
Reserved.
F
Duplication
of
this
manual
or
the
firmware
without
Aug.
13,
1990
Version
3.0
permission
of
Kantronics,
Inc.
is
prohibited.
Operations
Manual