- HP All-in-One Printer Manual

130 Theory of operation Q2431-90912
PJL overview
Printer job language (PJL) is an integral part of configuration, in addition to the standard printer
command language (PCL). With standard cabling, PJL allows the printer to perform functions
such as:
● Two-way communication with the host computer through a bidirectional parallel
connection. The printer can tell the host about such things as the control panel
settings, and it allows the control panel settings to be changed from the host.
● Dynamic I/O switching allows the printer to be configured with a host on each I/O.
The printer can receive data from more than one I/O simultaneously, until the I/O
buffer is full. This can occur even when the printer is offline.
● Context-sensitive switching allows the printer to automatically recognize the
personality (PS or PCL) of each job and configure itself to serve that personality.
● Isolation of print environment settings from one print job to the next. For example, if
a print job is sent to the printer in landscape mode, the subsequent print jobs print in
landscape only if they are formatted for landscape printing.
PML
The printer management language (PML) allows remote configuration and status readback
through the I/O ports.
Control panel
The formatter sends and receives printer status and command data to and from a control panel
PCA.