Localtalkcircuit - Epson C11C605001 - DFX 9000 B/W Dot-matrix Printer Service Manual

Service Manual
Circuit
2.2.1.7 RS-422
This circuit uses the RS-422 receiver/driver IC MC34050 (IC4) to change the signal level from the
signal level.
The E05A93 standard cell changes serial (RS-422) data to parallel data.
Parallel Data
..... ----------""-
2.2.1.8 LocalTalk Circuit
The LocalTalk arcuit is an optional C82326* I/F board. It uses three ICS: 85C30 (IC3), 26LS30 (ICI),
and 26LS32 (IC2). The 85C30 (IC3) changes parallel data to serial data or serial data to parallel data.
It is controlled by E05A93 (IC17) at the C135 MAIN board.
The 26LS30 (IC1) and the 26LS32 (IC2), which are signal level change ICS, changes a TTL signal
level to a LocalTalk signal level (compatible with RS-422 signal level).
Cl
35 MAIN Board
2.2.1.9 Optional Typ+B Interfaoe
This printer supports an EPSON Type-B optional interface, which is controlled by the INH and BIF
signals from the E05A93 (IC17).
Rev. A
Transmit
.
-------------- "+
Receive
Figure 2-43. RS-422 Circuit
CN1
CN7
Data Bus
Address
Bus
Figure 2-44. LocalTalk Circuit
Serial
Data
. .
. 26LS32
4
Operating Principles
LocalTalk
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