Epson Action Laser II - Manual (Page 201)

Interface Specifications
Handshaking
The printer’s serial interface can use DTR (Data Terminal Ready)
signal levels and XON/XOFF communication protocols either
separately or in combination
XON/XOFF protocol
When the vacant area for data in the input buffer drops to 128 bytes,
the printer outputs an XOFF code, indicating that the printer cannot
receive more data. Once the vacant area for data in the buffer
recovers to 256 bytes, the printer outputs an XON code, indicating
that the printer is again ready to receive data.
XON/XOFF protocol can be enabled using SelecType. The factory
setting is “ENABLE.”
DTR/DSR
protocol
When the printer can receive the data, the printer sets the DTR signal
level to high (SPACE). When the printer cannot receive data, the
printer sets the DTR signal level to low (MARK). If the DTR menu in
SelecType is set to off, the DTR signal is always treated as high
(SPACE.) The printer sends the TXD (transmitted data) only when
the DSR signal level is set to high (SPACE) except the DSR menu in
SelecType is set to off. If the DSR menu in SelecType is set to off, the
DSR signal is always treated as high (SPACE.)
DTR/DSR protocol can be enabled using SelecType. The factory
settings are DTR “ON” and DSR “OFF.”
Error handling
A * character is printed if a parity error, framing error, or over-run
error is detected.
8-18 Technical Specifications