Epson FX-80 Operation Manual page 174

NOTES:
1. "Direction" refers to the direction of signal flow as viewed from the printer.
2. "Return" denotes "TWISTED PAIR RETURN" and is to be connected at signal
ground level.
As to the wiring for the interface, be sure to use a twisted-pair cable for each signal
and never fail to complete connection on the Return side. To prevent noise
effectively, these cables should be shielded and connected to the chassis ofthe host
computer and the printer, respectively.
3. All interface conditions are based on TTL level. Both the rise and fall times of
each signal must be less than 0.2 p.,s.
4. Data transfer must not be carried out by ignoring the ACKNLG or BUSY signal.
(Data transfer to this printer can be carried out only after confirming the
ACKNLG signal or when the level of the BUSY signal is "LOW".)
5. Under normal conditions, printer cable pins
11, 12
and
32
are activated when out
of paper is detected.
ESC 8 code disable pins 11 and32 from the PE (Paper-End) signal, but it does
not disable pin 12.
Although most computers do not monitor pin 12, those which do (e.g, TRS-80)
will halt printing when the paper is out. Therefore, ESC 8 code is ineffective with
these computers.
(4) Data transfer sequence
The figure below shows the sequence for data transmission.
BUSY
ACKNLG
DATA
STROBE
-~~-+--,~ 0.5
J.tS
(Min.)
0.5
J.ts
(Min.)
0.5
J.ts
(Min.)
. Parallel Interface Timing
B-3
Approx. 5 J.ts
A rox.7}Js