Serial Interface - Epson LQ-1050 Technical Manual

REV.-A
2.3.2.2

Serial Interface

Operating Principle
The two handshaking methods are as follows:
status . . .
a )
The signal is set to SPACE
the printer is in an error state or when the vacant area of the input buffer reaches 256 byte or less.
In this way, handshaking with the host is accomplished by setting the status
or MARK using the
( +
( -VI
(
( -v)
NOTES: 1. The value of "T"
2. The word structure of serial data is:
1 start bit + 8 data bits + parity (Odd, Even, or none) + 1 or more stop bit.
X-ON/X-OFF protocol . . . Sent on the
b)
Handshaking is accomplished by sending either X-ON ( 11 H) or X-OFF(13H) over the
host. When the printer can accept data, the printer send a X-ON code, the printer becomes busy,
then send a X-OFF code to the host computer. The X-OFF code is sent to the host when the vacant
area of the printer input buffer reaches 256 byte or less, or when the printer is in an error state (Refer
to Figure 2-32.).
-v)
( +1/)
-v)
NOTES: 1. The value of "T"
2. The
1 start bit + 8 data bits + parity
(REV) signal
when the printer can accept data and is set to MARK (–V) when
signal. (Refer to Figure 2-3 1.)
- - - - - -
1
according to the input data.
Fig. 2-31. Handshaking with
Data
start
Bit
according to the input data.
word structure of serial data is:
Fig. 2-32. Handshaking with X-ON/X-OFF Protocol
L
Data Bit
Start
line
Stop Bit
Stint Data
[ X - O F F )
(Odd, Even, or none) + 1 or more stop bit.
2-32
to either SPACE
"T "
—
—
Stap Bit
1
=
1
Signal
'T "
line to the