Epson EPL-N2000 Reference Manual page 172

nStrobe/HostClk
Compatibility mode: Latch pulse used to read in print data. When low,
DATA is valid.
negotiation phase: Latch pulse used to read in extensibility request values.
Nibble mode: Always high.
ECP mode: Used to transfer data and addresses from the host to the
printer with handshaking via PeriphAck (Busy).
DATA1 to DATA8 (bidirectional, but may always be an input if
ECP or EPP mode is not supported)
Compatibility mode: Forward channel data.
negotiation phase: Extensibility request value.
Nibble mode: Not used.
ECP mode: Bi-directional data.
nACK/PtrClk/PeriphClk
All modes: DATA8 is the MSB, DATA1 is the LSB.
Compatibility mode: Acknowledgment low pulse in order to indicate that
data was transferred from the host.
negotiation phase: Low signal indicates IEEE 1284 is supported; set to
high afterwards to indicate that the Xflag and "data available" flag are
valid.
reverse data transfer phase: In nibble mode, a low signal indicates that the
nibble data is valid.
reverse idle phase: When switched from low to high, generates an
interrupt that notifies the host that there is data available.
ECP mode: Used to transfer data from the printer to the host with
handshaking via HostAck (nAutoFd).
A-8
Technical Specifications