Pseudopolling/lmmediate Block Transmit
(PINS 7 and 10)
With
no strap installed, SUPER BEE
will
do
an
immediate block transmit
if
"Clear-to-Send"
is
true
(if
so
strapped on
pin 6
to
11
block/page transmit).
If
strap
is
installed, SUPER
B'EE
waits
for
an
ETB
(Control
W)
before transmitting.
Parity Test (PINS 8 and 9)
With no strap installed, SUPER BEE
checks incoming data
for
even
parity
when
operating asynchronously and odd
parity
when operntinq synchronously.
If
an
invalid character
is
sensed
during
parity
check, the character
is
replaced on the
display by a
parity
error symbol (reverse
video backward question mark). With
this strap installed, no
parity
check
is
made. Transmitted data
is
in the
same
sense
as
received data,
with
the excep-
tion
that
data
is
transmitted
with
a mark
parity
bit
with
strap installed.
3.5.8 Printer
Baud
Rate and
TTL
Transmit Clock
Strapping
The switch board
of
the Interface assembly
includes the components and strapping
to
deter-
mine and produce the
TTL
transmit clock,
1 O-or-11-bit word, baud rate
multiplier
and baud
rate
for
the
printer
port
only
(see
Figure 3-3).
The
printer
TTL
logic level,
if
unstrapped,
is
not
present.
If
desired, selection
of
a
TTL
transmit clock
can
be
made by strapping one
of
five pins
to
produce one
to
16 times the inter-
nal clock baud rate. (
1,
2,
3, 8
or
16).
The
printer
RS-232 level baud rate
is
determined by strapping one
of
the pins
on
the
switch board. A baud rate
of
1,
2, 4, 8, 16,
32
or
64
can
be
selected by strapping the apporp-
riate pins.
3-7
The determination
of
1 O-or-11-bit
word
structure
is
made by strapping the appropriate
connector pins.
If
no strp
is
added, the
printer
port
will
output
11-bit
words.
With
a strap added,
the
output
wi
II
be
a 10-bit word. This strapping
feature also provides the baud rate
multiplication.
With
no strapping (
11-bit
word)
multiplies
the
baud rate by 150.
By
strapping (
10-bit
word),
it
multiplies the rate by 110. The baud rate
can
vary,
therefore,
from
110
to
9600
baud.
3.5.9 Current
Loop
Adapter
- - -
· · The current loop adapter
is
dual purpose.
a.
A
modified
TTY
interface
for
some mini-
computers features
an
open collector
output
and
photoisolated
input.
The computer should
be
writ-
ten
50
ft.
of
the terminal.
b.
A single
or
balanced current
loop
inter-
face
can
be
used
up
to
2000
ft.
away.
With
twisted,
shielded 2 pair cable and slower baud rates.
It
may
be
useable up
to
6000
ft.
A photoisolated
input
and
20
ma
current
driver
is
required
at
the
other
end.
An
operational
amplifier bipolar
output
(+15
to
-20
volt)
drives
about
20
ma
of
current through the loop.
Up
to
1000 ohm
of
loop
resistance
can
be
tolerated.
(Note - the
amplifier
output
can
drive
an
RS232
input
if
desired).
In either a
or
b mode above, the receive
line data
is
internally
buffered and
or'ed
with
data
from
the RS232 connector. Data
can
be
input
on
either
but
not
simultaneously. Data
is
output
simu-
ltaneously on both.
Either open collector
or
bipolar
20
ma
current balanced/unbalanced interfaces are provided
for
at
the J 14 connector. A male am phenol 17-
20150-1 cable connector plugs on
to
J14 and
is
jumpered
to
do
the desired functions.
The
J12 1/0
RS232
port
can
be
used
while the
Jl
4
port
is
con- -
nected
but
received data
is
buffered and OR'ed
from
both. This prevents simultaneous reception
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