Epson PX-8 Technical Manual page 10

REV.-A
External interfaces (shown in Table 1-4) and two ROM capsules on the board provide a system
configuration suitable for your needs or implementation of an application program. An auxiliary
rechargeable battery of 90 mAH is also incorporated which supplies power in order to ensure
normal circuit operation when the voltage of the main battery falls down below a certain value.
Table 1-4 External Interfaces
Item Function Note
RS-232C
11 0
~
19200 BPS, Operator-selectable: transmission speed,
RS-232C level X-ON/OFF, etc.,
SERIAL
38400 BPS MAX., Operator-selectable: transmission speed,
RS-232C level X-ON/OFF, etc.,
Barcode Read at TTL level Read program and bar code reader are required.
Analog input
Analog or joystick input Analog input line has +5V pull up function.
(with trigger)
External speaker
o
~
6Voutput
8.0
0.2W
1.3.2 Microcassette
The microcassette consists of a control board and drive mechanism. Operations such as FF,
REW, etc. are controlled by software, resulting in high reliability compared with manual control.
Increased chip implimentation has permitted a reduction in size of the control board.
This cassette drive operates at a tape speed of 2.4 cm/s, and reads or writes data effectively utiliz-
ing a tape counter and directory which contains file names, file starting addresses, etc.
Fig. 1-4
Mechanical components include a tape drive motor and its driving mechanism, R/W heads and
their mechanisms, reels, etc. The control board controls the revolving speed of motor, load/
unload of R/W heads and R/W operation.
To enable sound output, it provides signals to an internal or external speaker after amplifying them
twice. For reading data, duplicated amplification circuits eliminate high frequency component
(noise) and detect the peak of signal to ensure highly reliable sound output.
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