PacComm TINY-2 - Flow Control Mechanisms

OPERATING
INSTRUCTIONS
Flow
Control
If
any
characters
are
typed
during
these
CMdtime
intervals
(even
Command
Mode
entry
characters)
the
escape
will
be
aborted
and
all
the
Command
Mode
entry
characters
that
have
been typed will be sent as packet data. If you set CMdtime
to
zero
you
will
not
be
able
to
escape
from
Transparent
Mode
using
this procedure.
You
can
also
enter
Command
Mode
from
Transparent
Mode
by
sending
a BREAK
signal. If the computer
sending
data to the
packet controller
inadvertently
sends a data signal interpreted
as
a
BREAK,
set
BReak
OFF
to
disable
the
packet
controller’s
response
to
the
signal.
.
Pp S input buffer may fill up in Command
Mode
if
you
try
to
type
too
long
a
command.
In
Converse
Mode
the
buffer
may
fill
up
because
you
are
using
a
faster
serial
port
baud
rate
than
the
radio
data
rate,
or
radio
data
transmission
may
have
slowed
down
because
of
noise
or
other
users
on
the
channel,
or
the
person
or
computer
at
the
other
end
may
have
stopped
output
from
that
packet
controller.
The
packet
control-
ler
will
signal
the
computer
to
stop
sending
data
when
there
is
room
remaining
for
about
80
characters
in
the
buffer.
When
the
buffer
fills
up
entirely,
data
will
be
lost.
When
the
buffer
empties
so
that
there
is
room
for
at
least
270
characters,
the
packet
controller
will
signal
the
computer
to
start
sending
data
again.
There
are
two
methods
of
providing
flow
control
which
are
supported
by
the
packet
controller.
XON/XOFF
flow
control,
sometimes
called
“software
flow
control,”
is
accomplished
by
sending
a
special
character
(usually
<CTRL-S>)
to
request
that
the
output
stop
and
another
special
character
(usually
<CTRL-Q>
)
to
restart
output.
Hardware
flow
control
may
be
used
if
both
computers
use
the
Clear
To
Send
(CTS)
and
Re-
quest
To
Send
(RTS)
lines
of
the
RS-232C
standard.
Some
commonly
used
terminal
programs
and
file
transfer
programs
for
home
computers
do
not
implement
flow
control
in
software,
and
many
serial
ports
do
not
support
hardware
flow
control.
Although
the
RTS
and
CTS
lines
appear
at
the
connec-
tor,
they
may
not
be
used
unless
the
software
reads
the
state
of
the
crs
line.
If
you
find that
the
packet
controller
seems
to
lose
data
during
file
transfers,
you
should
immediately
suspect
a
flow
control
problem.
XON/XOFF
Flow
Control
If
you
are
using
a
terminal
(rather
than
a
computer)
or
if
your
computer
does
not
support
RTS/CTS
flow
control,
you
should
20
Operating
Manual,
4th
Ed.
©
PacComm,
1990