-
_______
APPENDIX C
INTERFACE
CABLE
Switch 13: This switch
is
factory
set
to
ON
so
that the printer
waits until the
print
buffer
has
room for
only
32
more bytes before sending a busy signal to the com-
puter. If you discover that you are losing data,
set
this switch to OFF; the printer
will
send a busy
signal when room for
only
256 more characters
remins in the print buffer.
Switch 14:
Factory
set
ON
for a 200-ms busy time (the time
it
takes the printer to empty the
print
buffer and be
ready to receive data), this switch can be
set
to OFF
if
your computer requires more time to process a
response to a busy signal. This situation
normally
arises when the printer
is
not connected directly to
the host computer.
NOTE: Those switches not mentioned in the list above are not currently used and
should be left in their factory settings.
Super-Speed Serial Board Diagnostic
Tests:
If
you
would
like to check
your
serial cable to ensure it
is
sending
and receiving the right signals, you
can
run either
of
the
following
tests.
For
the circuit test, however, you need to purchase (or make) a
test cable
as
shown
below
then
follow
the directions under "Perfor-
ming the Circuit Test."
1.
Purchase or make a test cable, using a Cannon DB-25P plug, to
jumper
the
following
pins:
Transmit data 2
--------.,
Receive data 3
__
0--------'
Request to
send
4----
1
Clear to send 5 _
..
o-----~
Carrier detect 8 .. I
Supervisory
send
data
11--
Data terminal ready
20----,
Data
set
ready 6
__
o-------!
125
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