Epson Stylus COLOR 440 Service Manual page 29

EPSON Stylus COLOR 440, 640, and 740
Table 1-12 shows pin assignments for the reverse channel. (Reverse
channel is the mode in which all data is transferred from the printer to
the computer.) For these signals, a twisted pair line is used, and the
return side is connected to the signal GND.
Pin No.
1
2 to 9
10
11
12
13
14
31
32
36
18
35
17
16,33, 19 to
30
15,34
Notes: In/Out refers to the direction of signal flow from the printer's point of view.
An overscore above a signal name means that signal is active LOW.
Table 1-12. Pin Assignments for Reverse Channel
Return GND
Signal Name
Pin
HostClk
Data0 to Data7 20 to 27
PrtClk
PtrBusy, Data Bit-3,7
AckData Req, DataBit-2,6
Xflag, DataBit-1,5
HostBusy
INIT
DataAvail, DataBit-0,4
1284-Active
Logic-H
+5 V
Chassis GND
GND
NC
In/Out
19 In Host clock signal.
The DATA0 through DATA7 signals represent data
bits 0 through 7. Each signal is at HIGH level when
In data is logical 1, and at a LOW level when data is
logical 0. These signals are used to transfer the 1284
extensibility request values to the printer.
28 Out Printer clock signal.
Printer busy signal and reverse channel transfer data
29 Out
bit 3 or 7.
Acknowledge data request signal and reverse channel
28 Out
transfer data bit 2 or 6.
X-flag signal and reverse channel transfer data bit 1 or
28 Out
5.
30 In Host busy signal.
Not used.
30 In
Data available signal and reverse channel transfer
29 Out
data bit 0 or 4.
30 In 1284 Active Signal
— Out Pulled up to +5 V via 3.9K ohm resistor.
— Out Pulled up to +5 V via 3.3K ohm resistor.
— — Chassis ground.
Signal ground.
— —
— — Not connected.
Chapter 1 Product Description
Functional Description
20