SANEI ELECTRIC SK1-21A, Technical Manual

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４３
SK1-21A/31A
(3) Hardware control
High/Low of RTS signal is used to control data transmission to the host system.
RTS signal becomes low if the receiving buffer is filled out curtain level ( ① )
The host side should stop sending data if RTS signal is low. If the data in the input buffer is
reduced to curtain level, RTS signal goes high and re-start sending remained data (
②
)
RTS
RxD
PRINT
PAPER
POWER ON
buffer
②
EMPTY
buffer
①
(4) Software control(XON/XOFF)
Xon(11H)
／
Xoff(13H) signal is used to control data transmission to the host system.
Xoff signal is sent to host system if the receiving buffer is filled out curtain level.(
①
)
The host side should stop sending data if Xoff signal is received. If the data in the input
buffer is reduced to curtain level, Xon signal is sent to the host system and re-start sending
remained data (
② )
T x D
R x D
P R IN T
X o n
X o f f
X o n
X o n
R T S
X o f f
P AP ER
EM P TY
P OWE R ON
bu f fe r
①
bu ff er
②
（
5
）
Conditions of input / output signal
Rate value
Item Condition
Min. Typ. Max.
Unit
High input voltage RxD 、 CTS +2.8 ― +15 V
Low input voltage RxD
、
CTS -15 ― -2.8 V
High output voltage TxD
、
RTS
(RL=3K Ω )
+2.8 ― +15 V
Low output voltage TxD 、 RTS
(RL=3K Ω )
-15 ― -2.8 V