<s>
The	O
Epson	B-Device
PX-4	I-Device
(	O
HC-40	O
or	O
HX-40	O
)	O
is	O
a	O
portable	O
CP/M	B-Application
based	O
computer	O
introduced	O
in	O
1985	O
.	O
</s>
<s>
The	O
screen	O
was	O
40×8	O
characters	O
physical	O
,	O
but	O
80×25	O
or	O
40×50	O
virtual	O
,	O
making	O
it	O
almost	O
compatible	O
with	O
the	O
Epson	B-Device
PX-8	I-Device
Geneva	I-Device
.	O
</s>
<s>
It	O
was	O
targeted	O
as	O
successor	O
of	O
the	O
Epson	B-Device
HX-20	I-Device
portable	O
,	O
which	O
was	O
very	O
popular	O
with	O
field	O
engineers	O
.	O
</s>
<s>
Inheriting	O
the	O
ROM	O
capsules	O
from	O
the	O
Epson	B-Device
PX-8	I-Device
Geneva	I-Device
,	O
it	O
added	O
a	O
cartridge	O
bay	O
(	O
similar	O
but	O
incompatible	O
with	O
the	O
Epson	B-Device
HX-20	I-Device
)	O
,	O
for	O
which	O
Epson	O
offered	O
several	O
printers	O
,	O
micro-cassette	O
drive	O
,	O
modem	O
,	O
EPROM	O
writer	O
,	O
DMM	O
(	O
Digital	O
Multimeter	O
Module	O
)	O
,	O
RAM	O
and	O
ROM	O
cartridges	O
.	O
</s>
<s>
Other	O
features	O
were	O
the	O
Serial	O
and	O
RS232	O
port	O
,	O
barcode	O
reader	O
interface	O
like	O
with	O
the	O
Epson	B-Device
PX-8	I-Device
Geneva	I-Device
.	O
</s>
<s>
New	O
were	O
a	O
cassette	O
port	O
and	O
parallel	B-Device
printer	I-Device
port	I-Device
.	O
</s>
