Epson EPL-6000 User Manual page 198

Notes
All interface conditions are based on TTL level. Both the rise
and fall of each signal must be less than 0.2 microseconds.
The column heading "Direction" refers to the direction of
signal flow as viewed from the printer.
"Return" denotes the twisted-pair return, to be connected at
signal ground level. For the interface wiring, be sure to use a
twisted-pair cable for each signal and to complete the
connection on the return side. These cables should be shielded
and connected to the chassis of the host computer and the
printer.
Interface timing
The figure below shows the timing for the parallel interface.
SELECT
DATA 1-8
DATA STROBE
BUSY
ACK
A: 1 µs (min.) B: 1 µs (min.)
Interface Specifications
C: 1 µs (min.)
Technical Specifications B-9
D: approx. 6 µs