Vector 4 - Page 104

EXHIBIT 1I-19 STANDARD SERIAL PROTOCOL
This serial printer protocol uses "Hardware Handshaking" signals, Pin 4 of the
DB-25 connector is used as the "Clear to Send Signal®.
freee Software may send
T 1N CONTROL SEQUENCE initialization sequence.
\ CUFFER initializ qu
USART qgflgmm. eacles et Depends On prlnter
L — —p | L1 [.'] [ fl —— protocol.
FAPER
PRINTER
M
ata
|
T
Software
sends
data
to
T TR e BUFFER printer.
USART 3.’. JLeee :-:Z'.*l."".&& l ‘,':'. .‘_: :{: .:: :.'.
. : ® oMo *les b, 00 ,
_L____, PIN 3
FAPER
PRINTER
] Printer buffer is receiving
1 i il data and printer is
BUFFE < . .
USART
LA
H:l
printing
data.
- | —— e
o i
it
H
PAPER
PRINTER
"‘m; "Hardware Handshaking"
| [ i signal goes LOW. Buffer
USART
[,1}31]
%FTH
]!“’1
is
full
and
emptying
while
i
=
PIN
4
el
T
)
printer
continues
printing
nten—r—
l]im
d&ta.
PAPER
PRINTER
Printer buffer is receiving
]
data
and
printer
is
BUFFER _ printing data.
- [T ER
PRINTER
II 5-13