Rs-232C Serial Interface Specifica~Ions; Fig. 1-9. Hand Shaking Of Rs-232C Interface; Table 1-13. Serial Interface Handshaking - Epson LQ-1050 Technical Manual

REV.-A
1.3.2 RS-232C Serial Interface Specifications
Data Transmission Mode
Synchronization
Handshaking
MARK
SPACE
MARK ( - 12VI
SPASE ( + IZV)
Word Length
Start bit
Data bit
Parity bit
Stop bit
Bit Rate
Logic Level
Data Transmission Timing
Asynchronous
By DTR (REV) signal or X-ON\OFF protocol
Refer to Table 1-13 and Figure 1-9.

Table 1-13. Serial Interface Handshaking

X-ON/OFF protocol
X-OFF (13H)
X-ON (1 1 H)
I

Fig. 1-9. Hand Shaking of RS-232C Interface

8
Odd, Even, or none
(selectable by DIP switches 2-3 and 2-4)
1 bit or more
300, 1200, 4800, or 9600 BPS
(selectable by DIP switches 2-5 and 2-6)
EIA level, MARK: logical 1 (–3 - –27 V)
See
Figure 1-10.
When the number of bytes remaining in the input buffer
reaches 256 or less, the signal level goes to MARK, or a
X-OFF code is sent out to the host computer. This indicates
that the printer is not ready to receive data.
When the number of bytes remaining in the input buffer
reaches 512 or more, the signal level goes to SPACE, or a
X-ON code is sent out to the host computer. This indicates
that the printer is ready to receive data.
I
5 1 2 b y t e 256byte O
1
1
X-OFF
X-ON
SPACE: logical O (+3 - +27 V)
1-14
Description
byte Input Buffer Vacant Area
X-ON/X-OFF Protocol