Host Interface Circuit; Drawer Kick-Out Drive Circuit - Casio UP-250 Technical Manual

A near-end detector is an option that detects the remaining amount of a paper roll. The input
signal to the CPU (U5) becomes LOW when a paper near-end is detected.
+5V
U5
RE
11
P64/AN4
12
P65/AN5
HP DET
9
P62/AN2
NE
GND

Host interface circuit

The printer has universal interfaces for connection to the host computer. There are three kinds of
interfaces:
EIA/TIA RS-232 intrface
IEEE 1284 interface
EIA/TIA RS-485 interface
See the interface circuit board diagrams in the Appendix.

Drawer kick-out drive circuit

Activating the DKD1 and DKD2 signals from the CPU (U5) causes transistors Q29 and Q30 to
turn on. This causes transistor array QM5 to turn on, and the drawer drive signal is output. The
drawer status signal DK_S, which indicates whether or not the drawer is open, is input to the
CPU (U5), allowing the host to check the status via the interface.
+5V
R36
R38
R53
C22 C23 C46
Figure 2-22 Various detector circuits
+5R
R40
1
REC
2
R37
HPC
3
R39
4
R16
C44
NEC 1
2
— 47 —
Mechanism 1
Printer mechanism
CN8
+5V
1
H.P
2
GND
3
R.E
4
1 2
Mechanism 2
CN11
1 2
N.E
1
GND
2