Epson Stylus Photo 720, Service Manual

Page: 13 / 154

EPSON Stylus Photo 720 / EPSON Stylus Photo EX3 Revision A
Product Description Interface Specification 13
1.3 Interface Specification
This printer has IEEE-1284 parallel interface and USB interface as standard.
1.3.1 IEEE-1284 Parallel I/F (Forward Channel)
Forward channel is the mode to transfer the ordinary printing command to the printer
side from the PC side.
NOTE: I/F cable is recommended to be in minimum length.
The connector pin assignment is described below. For these signals described in the
table, use the twist pair wire and connect the return side to the signal GND.
1.3.2 IEEE-1284 Parallel I/F (Reverse Channel)
Reverse channel is used to transfer the information data from the printer side to the PC
side.
Table 1-3. Parallel I/F Specification (F-Channel)
Item Specification
Transmission mode 8bit parallel
Synchronization By STROBE pulse supplied from the external
Handshaking By BUSY and ACKNLG signal
Signal Level TTL level (IEEE-1284-Level 1 device)
Adaptable connector 36 pin 57-30360 (amphenol) or equivalent
Table 1-4. Connector Pin Assignment and Signals (F-Channel)
Pin No.
Return
GND Pin
Signal
Name
From Function Description
1 19 -STROBE PC
The strobe pulse for the printer to read data.
Pulse width requires min. 0.5
µ
s (500ns).
High at normal condition. Receives data after
shifting Low.
2-9 20-27 Data0-7 PC
The DATA 1 through DATA8 signals
represent data bits 1-8, respectively.
10 28 -ACKNLG Printer
A low signal indicates the printer can accept
data. Pulse width is 0.5 (default) or can be set
at 2
µ
s.
11 29 BUSY Printer
A high signal indicates that the printer cannot
receive data. The signal becomes high under
the condition below;
-Receiving data.
-Error.
-Other I/F receiving data.
12 28 PE Printer A high signal indicates paper-out error.
13 28 SLCT Printer
Always at high level. Pulled up to +5V via
1.0K
Ω
resistor.
14 30 -AFXT PC Not used.
31 30 -INIT PC
The printer is initialized by the width of min.
50
µ
s Low pulse input.
32 29 -ERROR PC A low signal indicates printer error condition.
36 30 -SLIN - Not used.
18 - Logic H -
Always at high level. Pulled up to +5V via
3.9K
Ω
resistor.
35 - +5V -
Always at high level. Pulled up to +5V via
1.0K
Ω
resistor.
17 - Chassis - Printer chassis GND.
16, 33
19-30
- GND - Twist pair return GND.
15, 34 - NC - Not used.
Table 1-4. Connector Pin Assignment and Signals (F-Channel)
Pin No.
Return
GND Pin
Signal
Name
From Function Description