Epson EPL-5700 Reference Manual page 95

PError/AckDataReq/nAckReverse
Compatibility mode: High signal indicates that a feed jam
occurred in the paper supply section, or that there is no paper in
the paper-tray or cassette.
Negotiation phase: High signal indicates whether or not IEEE
1284 is supported or not. Afterwards, this signal conforms with
nDataAvail (nFault).
Reverse data transfer phase: In nibble mode, this signal serves as
nibble data bit 2 and then 6.
Reverse idle phase: High until the host requests a data transfer.
Afterwards, this signal conforms with nDataAvail (nFault).
ECP mode: Low signal authorizes nReverseRequest. The host
looks at this signal in order to determine whether or not it has
permission to drive the data signals.
Select/Xflag
Compatibility mode: Always high
Negotiation phase: Xflag indicates the extensibility flag. Used to
respond to the extensibility request value sent from the host.
Reverse data transfer phase: In nibble mode, this signal serves as
nibble data bit 1 and then 5.
Reverse idle phase: Same as negotiation phase
ECP mode: Same as negotiation phase
nAutoFd/HostBusy/HostAck
Compatibility mode: Not used
Negotiation phase: In order to request 1284 mode, this signal is
set low and IEEE 1284active (nSelectln) is set high. Afterwards,
this signal is set high when PtrClk (nAck) is set low.
Technical Specifications
A
A-9