Appendix B: Parallel Interface
B-1. Interface Specifications
The operating specifications of the parallel interface are as follows.
(1) | Data transfer rate | : | 1000 to 6000 characters per second | |||
(2) | Synchronization | : | Via externally supplied |
| pulses | |
STROBE | ||||||
(3) | Handshaking | : | ACK | and BUSY signals | ||
(4) | Logic level | : | Compatible with TTL level |
B-2. Interface Timing
ACK
Approx.9 ∝s
Data
STROBE
BUSY
T | T | T |
|
|
|
T:more than 0.5 ∝s
APPENDIX
Fig.
| Signal Name | Circuit Example |
| 4.7KΩ | 74HC Compatible |
| DATA |
|
| (To Printer) |
|
INPUT | 1KΩ | 74HC Compatible |
| ||
| STROBE | 100Ω |
| (To Printer) | 470pF |
OUTPUT |
| |
1.8KΩ | 74LS Compatible | |
| BUSY, ACK |
|
| (From Printer) |
|
Fig.
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