Cassette Interface; Specifications; Block Diagram - Radio Shack TRS-80 Service Manual

II. CASSETIE INTERFACE (26-3651)
1. SPECIFICATIONS
Output terminal: White mini-plug, output impedance: approx. 40 kohms,
output level: 3 - 50mV
Input terminal: Black mini-plug, input impedance: approx. 20 kohms,
input level: 2.5 - 5OV.
Remote control terminal: Gray sub mini-plug, 24V, lA or less.
Data recording format: Kansas City standards (JOOBPS).
Power source: (For remote control) Two AA size dry batteries.
Power consumption: 0.3W.
Battery life
Approx. 7 hours.
(for continuous operation):
Dimensions: 173mmW
X
114mmD
X
31.5mmH.
2. BLOCK DIAGRAM
MIC
-l
0
III
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III
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i
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III
8
...
Co
III
...
REMOTE
es.
...
r
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FILTER
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I
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p
CIRCUIT
LSI
H043110
SHAPING
~
I
I )
I
CIRCUIT
...
REMOTE
...
I
CONTROL
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)
I
CIRCUIT
LSI: Kansas City standards applied cassette tape
interface LSI.
Transfers serial data by the following frequenci
Data "1" ..... 2,340 Hz
CRYSTAL
Data "0" ..... 1,170 Hz
OSCILLATOR
Filter Circuit: Converts LSI's data pulse into AC
04
~
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Q.
VD03
...
Ql
<oJ
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Co
E CE2
8
c;;
4>1
l:
Sl
...
Ql
Q.
E
OP
0
...
u.
GNO
waveform for tape recorder.
Shaping Circuit: Converts AC waveform data from tape
recorder into square pulse for the LSI.
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