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Data Communications
Table 5-8. Keyboard Interface PCA Strapping Options for Point-to-Point
STRAP
A
B
C
D
E
F
G
STRAPPING OPTION
Function Key Transmission
Space Overwrite (SPOW)
Latch Enable
Cursor End-of-Line Wrap
Around
Line/Page
Paper Tape Mode
Fast Binary Read
Block Transfer Handshake
NORMAL OPERATION
(SWITCH CLOSED)
The escape code sequence generated
by the major function keys (such as,
ROLL UP, ROLL DOWN, etc.) are exe-
cuted locally, but not transmitted to the
computer.
Spaces typed will overwrite existing
characters.
At the end of each line, a local Carriage
Return and Line Feed are generated;
the cursor moves to the beginning of
the next line.
The terminal is set to transfer a line at a
time in Block Mode.
When the _
key is pressed with
III
key latched down, each tape record be-
gins with an LF and is terminated by a
CR.
The transmission rate is determined
by the BAUD RATE switch on the
keyboard.
In Block Mode, all data transfers to the
computer are sent upon receipt of a
DC1 from the computer.
OPERATON WITH
STRAPPING OPTION
(SWITCH OPEN)
The escape code sequences generated
by all keys are transmitted to the com-
puter. If operating in half duplex, the
function is also executed locally.
When the SPOW latch is off, overwriting
occurs as normal. When the SPOW
latch is on, spaces cause the cursor to
move forward but not overwrite any ex-
isting characters. The SPOW latch is
turned on by a Carriage Return, and off
by a Line Feed, Home or Tab.
A Carriage Return and Line Feed are
not generated at the end of each line.
The cursor remains in and overwrites
column 80.
Entire pages of information are trans-
ferred in Block Mode.
Each tape record is terminated by CR
LF.
When an ESC e (Fast Binary Read) is
issued by the computer, the baud rate
is switched automatically to 9600 baud
(if the terminal is equipped with car-
tridge tape units).
All Block Mode transfers (Le., cursor
sense, terminal and device status,
device I/O responses, display memory,
and function keys) are preceded by a
DC2. The terminal sends the DC2 upon
receipt of a DC1 from the computer.
After the CPU receives the DC2 from
the terminal, another DC1 is reqUired to
trigger transmission of data from the
terminal.
5-13
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