Epson TM-T70II, Техническое справочное руководство

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108
IEEE 1284 Parallel Interface
Modes
The IEEE 1284 parallel int erface s u ppor t s t he follow ing t wo modes.
Compatibility Mode
Compa ti b i l it y mode allows da t a t ra n sm i ss i o n from hos t t o pr int er o n ly: Ce nt ro ni cs-compa ti ble.
Specification
Reverse Mode
The t ra n sfer of s t a tu s da t a from t he pr int er t o t he hos t proceeds in t he ni bble or by t e mode.
Th i s mode allows da t a t ra n sfer from a n asy n chro n o u s pr int er un der t he co nt rol of t he hos t . Da t a
t ra n sfers in t he ni bble mode are made v i a t he ex i s ting co nt rol l in es in unit s of fo u r b it s (a ni bble).
I n t he by t e mode, da t a t ra n sfer proceeds by mak ing t he 8-b it da t a l in es b i d i rec ti o n al. Bo t h modes
fa i l t o proceed co n c u rre nt ly in t he compa ti b i l it y mode, t hereby ca u s ing half-d u plex
t ra n sm i ss i o n .
Mode Communication direction Other information
Compatibility mode Host

Printer communication Centronics-compliant
Reverse mode Printer

Host communication Assumes a data transfer from an
asynchronous printer
Data transmission 8-bit parallel
Synchronization Externally supplied STROBE signals
Handshaking ACK and BUSY signals
Signal levels TTL-compatible connector
Connector ADS-B36BLFDR176 (HONDA) or equivalent product
Reverse communication Nibble or byte mode