Metro Software publishes a product called Laser Twin which provides HP Laserjet
Series II emulation.
I haven't used the product in quite a while but I know that version 4.10 (which
is probably quite outdated now) did specifically support the LPB4.
The last address I have for Metro is:
1870 W.Prince Rd.
Suite 70
Tucson, Arizona 85705/USA
(602) 292-0313
FZ