Epson LQ-2170 User Manual page 135

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
5 DATA4
6 DATA5
7 DATA6
8 DATA7
9 DATA8
10 PtrClk
11 PtrBusy/
DataBit-3,7
12 ACkDataReq/
DataBit-2,6
13 Xflag/
DataBit-1,5
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:
00H: Request nibble mode of reverse channel
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
26 In
27 In
28 Out
29 Out
28 Out
28 Out
Description
Strobe pulse. Input data is
latched at falling edge of the
signal.
Bit 0: LSB Parallel input data to
the printer.
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7: MSB
Used to qualify data being
sent to the host. Set LOW then
HIGH to cause an interrupt
indicating to host that data is
available.
Data bits 3 then 7, indicate
forward channel busy status.
Data bits 2 then 6. Set HIGH
until host requests data
transfer, then follows
nData Avail (nFault).
Data bits 1 then 5.
A-15