Rs-232C Circuit - Epson C11C605001 - DFX 9000 B/W Dot-matrix Printer Service Manual

Operating Principles
Parallel Interface Circuit
2.2.1.5
Figure 2-41 shows the parallel interface circuit block diagram. Data sent from the host mmputer is
latched within the E05A93 by the STROBE
automatically to stop the host computer from sending additional data. The CPU
signal after reading the data from the E05A93, so that the printer is ready to receive more data from
the host computer.

2.2.1.6 RS-232C Circuit

This circuit uses the RS-232C receiver/driver IC MAX202 (IC19) to change the signal level horn the
signal level to the RS-232C signal level. lhis IC converts +5 VDC to +12 VDC and –12 VDC.
The E05A93 standard cell changes serial (RS-232C) data to parallel data.
Parallel Data -.................. ------"--"-b ?;;=;e-"-
2-28
signal.
——————b
Figure 2-41. Parallel Interface Circuit
Transmit
Figure 2-42. RS-232C Circuit
The outputs the
Latch
1-" "-:
serial
Data
MA)(2O2
BUSY signal
resets the
BUSY
Rev. A
.-., ..,
. . .;/
-'