6
3. Interfaces
3.1 Serial interface
1) Synchronization
: Not synchronized
2) Handshake
: RTS/CTS control
3) Transfer speed
: 19200bps, 38400bps
4) 1 word consists of :
Start bit : 1 bit fixed
Data bit
: 8 bits fixed
Parity bit
: No parity. Fixed.
Stop bit
: 2 bits fixed.
5) Signal polarity
RS-232C
Mark
: Theory “1” (-3V~-12V)
Space : Theory “0” (+3V~+12V)
6) Reception data (RXD signal)
Mark : 1
Space : 0
7) Reception control (RTS signal)
RS-232C
Mark
: Data transmission not available
Space : Data transmission available
Busy status (marked) will be :
z
At reception buffer full
z
During hardware being reset after power is set on
z
During software being reset
z
At
self-print
z
During firmware being rewritten
8) Transmission data (TXD signal)
RS-232C
Mark
:
1
Space
:
0
9) Transmission control (CTS signal)
The host indicates that data reception is available.
3.2 Input/output circuit
Serial interface signal
It is structured by the driver and receiver in accordance with RS-232C.
HIN202CA
TXD
RXD
TO CPU circuit
RTS
CTS
The signal level: Mark = -3 ~ -15V, Logic “1” Off
Space = +3 ~ +15V, Logic “0” On
