Connector
Return
pin
line pin
number
number
15
–
16
–
17
–
18
–
19 to 30
–
31
30
32
29
33
–
34
–
35
–
36
30
*1 Assigned as a signal name, without any function.
Notes:
1. Left-aligned signal names are in compati mode and right-aligned ones are in nibble mode.
2. The direction (input and output) refers to the printer.
3. Return line: Twisted-pair return line connected to the signal ground level
5-4
Table 5.1 Parallel interface signals (continued)
Signal
Compati mode
Direction
Nibble mode
–
Signal Ground (SG)
Frame Ground (FG)
–
Signal Ground (SG)
Input Prime
Input
(IN PRM)
Fault
Output
Data Available
–
–
+5 V
Output
(Select In)
Input
1284 Active
–
Not used
–
Logic ground level (0 V)
–
Printer chassis ground line
FG and SG are connected.
–
Not used
–
Twisted-pair return lines
Reserved (*1)
This signal goes low under the following printer
conditions:
(1) Offline
(2) Paper out
(3) Cover open
(4) Other printer error
Reverse data transfer phase:
This signal is set low when the printer is ready to
send data to the host. During the data transfer, it is
used as data bit 0 (LSB), then data bit 4.
Reverse idle phase:
This signal is used to indicate that data is available.
–
Not used
–
Not used
Pulled up to +5 V through a 1.0 k resistor
Reserved (*1)
This signal goes high to cause the printer to enter the
reverse data transfer phase (nibble mode).
Description