Epson LQ-2070 User Manual page 136

Extensibility request:
The following table lists the parallel connector pin assignments and
describes their respective interface signals.
Pin Signal name
no.
1
HostClk
2 DATA1
3
DATA2
4 DATA3
DATA4
5
6 DATA5
DATA6
7
8 DATA7
9 DATA8
10
PtrClk
11
PtrBusy/
DataBit-3,7
12
AckDataReq/
DataBit-2,6
13
Xflag/
DataBit-1,5
14 HostBusy
31
INIT
DataAvail/
32
DataBit-0,4
Specifications, Command Summary, and Character Tables
The printer responds to the extensibility
request in the affirmative when the
request is 00H or 04H, which means:
Request nibble mode of reverse channel
OOH:
transfer
04H: Request device ID in nibble mode of
reverse channel transfer
GND In/Out*
19 In
20
In
21
In
22 In
23
In
24
In
25
In
In
26
In
27
28 Out
29
Out
28 Out
28 Out
In
30
30 In
29 Out
Description
Host clock signal
Parallel input data to the printer.
bit 0:LSB
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7:MSB
Printer clock signal.
Printer busy signal and reverse
channel transfer data bit 3 or 7.
Acknowledge data request signal
and reverse channel transfer data
bit 2 or 6.
X-flag signal and reverse channel
transfer data bit 1 or 5.
Host busy signal.
Not used.
Data available signal and reverse
channel transfer data bit 0 or 4.
A-15