User Guide

Resolution Enhancement technology
The formatter contains circuitry for Resolution Enhancement technology (REt), which modifies the
standard video dot data on its way to the dc controller PCA to produce "smoothed" line edges. The
REt can be turned on or off from the control panel or from some software programs. The default
setting is medium.
NOTE The REt settings that are sent from software programs or printer drivers override the
control-panel settings.
EconoMode
The EconoMode setting uses up to 50% less toner than standard mode printing by reducing the dot
density. However, EconoMode does not extend the life of print-cartridge components. EconoMode,
which can be thought of as "draft mode," can be selected from the control panel (print-quality menu)
and through some software programs and printer drivers. The default setting is OFF.
CAUTION HP does not recommend full-time use of EconoMode. If EconoMode is used full-
time, it is possible that the toner supply will outlast the mechanical parts in the print cartridge.
NOTE EconoMode does not affect print speed or memory usage, or extend the life of the
print cartridge.
Input/output
The following sections discuss the input and output features of the product.
Parallel interface
The formatter receives incoming data through its bidirectional interface (IEEE-1284). The I/O
provides high-speed and two-way communication between the printer and the host, allowing the user
to change printer settings and monitor printer status from the host computer. The user can configure
the HIGH SPEED item on the control panel. The default setting (YES) makes it possible for the I/O to
run at the higher speeds that are supported by most newer computers. When set to NO, the parallel
interface runs at the slower mode that is compatible with older computers. The user can also
configure the ADVANCED FUNCTIONS item. The default setting (ON) accommodates two-way
parallel communications. The OFF mode disables the advanced functionality. The I/O is compatible
with the bidirectional parallel interface standard.
USB (HP LaserJet 4250/4350 Series printers only)
HP LaserJet 4250/4350 Series printers include a universal serial bus (USB) 2.0 connection
Embedded ethernet print server (HP LaserJet 4250/4350 Series printers only)
HP LaserJet 4250/4350 n, tn, dtn, and dtnsl models include an HP Jetdirect embedded print server
for connecting to a 10/100Base-TX network.
162 5 Theory of operation