User guide

Printer Communication Interfaces
A.2 The Serial Port
DTR Handshaking Control
When DTR handshaking protocol is selected, the DTR (Data Terminal Ready)
signal of the serial interface is raised and lowered to control data flow, as
follows:
• When just powered up and ready, the printer forces DTR high, signaling to
the data source that transmission may begin.
• When the number of characters in the input buffer reaches its upper
threshold, the printer forces DTR low, signaling the data source to stop
transmitting.
• When the number of characters in the input buffer falls to the lower
threshold, the printer forces DTR high again so that transmission may
resume.
If the Disconnect on Fault setup feature is set to ‘‘Not selected,’’ no special
action occurs with DTR in the event of an error condition, such as ‘‘out of
paper’’ or ‘‘cover open.’’ DTR is forced low (turned off) after the input buffer
reaches the upper threshold.
Similarly, when the error condition is removed, DTR will not be raised (turned
on) until the input buffer reaches the lower threshold.
When the Disconnect on Fault setup feature is selected, any condition that
brings up the fault indicator causes the DTR signal on the serial interface to
be dropped (turned off) until the fault is cleared.
XON/XOFF + DTR Handshaking Control
While XON/XOFF + DTR protocol is enbabled, DTR toggles between high and
low states at the same time that XON and XOFF characters are sent to the
host.
Note
This protocol applies to the LA600 MultiPrinter only.
A.3 The Parallel Port
The parallel port of the printer uses a Centronics type, 36-pin connector, and
the interface signals conform to the Centronics handshaking protocol. If you
intend to use only the parallel interface, the Communication Port Selection
feature should be set to ‘‘Parallel’’ by means of the setup facility.
A–4 Printer Communication Interfaces