<s>
Mera	O
–	O
Elzab	O
Meritum	B-Device
–	O
a	O
family	O
of	O
Polish	O
personal	B-Device
computers	I-Device
based	O
on	O
TRS-80	B-Device
Model	I-Device
I	I-Device
with	O
BASIC	O
Level	O
II	O
.	O
</s>
<s>
Design	O
of	O
the	O
Meritum	B-Device
began	O
in	O
1982	O
.	O
</s>
<s>
It	O
was	O
a	O
computer	O
using	O
a	O
Zilog	B-General_Concept
Z80	I-General_Concept
processor	O
that	O
could	O
be	O
replaced	O
by	O
the	O
U880	B-Device
made	O
in	O
East	O
Germany	O
.	O
</s>
<s>
Peripheral	O
chips	O
produced	O
in	O
Poland	O
by	O
CEMI	O
factory	O
for	O
the	O
MCY7880	B-General_Concept
processor	O
(	O
Intel	B-General_Concept
8080	I-General_Concept
clone	O
)	O
could	O
be	O
used	O
for	O
both	O
the	O
Z80	B-General_Concept
and	O
U880	B-Device
.	O
</s>
<s>
In	O
1987	O
Elwro	O
finished	O
production	O
of	O
Meritum	B-Device
as	O
it	O
started	O
manufacturing	O
its	O
personal	B-Device
computer	I-Device
for	O
schools	O
Elwro	B-Device
800	I-Device
Junior	I-Device
.	O
</s>
<s>
The	O
reception	O
of	O
the	O
computer	O
was	O
initially	O
positive	O
,	O
it	O
was	O
seen	O
as	O
the	O
first	O
polish	O
personal	B-Device
computer	I-Device
.	O
</s>
<s>
Besides	O
,	O
TRS-80	B-Device
was	O
an	O
unknown	O
computer	O
in	O
Poland	O
.	O
</s>
<s>
Based	O
on	O
U880	B-Device
processor	O
at	O
2.5	O
MHz	O
.	O
</s>
<s>
It	O
was	O
slightly	O
modified	O
TRS-80	B-Device
Model	I-Device
I	I-Device
BASIC	O
Level	O
II	O
.	O
</s>
<s>
Display	O
circuit	O
was	O
similar	O
to	O
TRS-80	B-Device
,	O
it	O
supported	O
64×16	O
or	O
32×16	O
monochrome	O
text	O
mode	O
only	O
;	O
low	O
resolution	O
128×48	O
graphic	O
mode	O
simulated	O
by	O
semigraphics	O
.	O
</s>
<s>
Similar	O
to	O
TRS-80	B-Device
there	O
were	O
no	O
lower	O
case	O
characters	O
.	O
</s>
<s>
The	O
computer	O
was	O
equipped	O
with	O
parallel	O
and	O
serial	O
port	O
not	O
compatible	O
with	O
TRS-80	B-Device
Expansion	O
Interface	O
.	O
</s>
<s>
Parallel	O
port	O
was	O
based	O
on	O
MCY7855	O
universal	O
I/O	O
chip	O
which	O
was	O
Polish	O
clone	O
of	O
Intel	B-Device
8255	I-Device
.	O
</s>
<s>
Serial	O
port	O
used	O
MCY7851	O
(	O
clone	O
of	O
Intel	B-Device
8251	I-Device
)	O
;	O
transmission	O
rates	O
from	O
95	O
to	O
9600	O
bauds	O
were	O
possible	O
.	O
</s>
<s>
In	O
addition	O
,	O
hardware	O
counter	O
chip	O
8253	B-Device
was	O
available	O
.	O
</s>
<s>
Meritum	B-Device
II	O
consists	O
of	O
the	O
Meritum	B-Device
I	O
model	O
2	O
computer	O
and	O
an	O
external	O
floppy	O
disk	O
unit	O
with	O
two	O
5¼″	O
drives	O
.	O
</s>
<s>
A	O
second	O
universal	O
I/O	O
chip	O
8255	B-Device
(	O
MCY7855	O
)	O
has	O
been	O
added	O
for	O
communication	O
with	O
the	O
floppy	O
disk	O
unit	O
.	O
</s>
<s>
The	O
computer	O
could	O
work	O
under	O
the	O
control	O
of	O
CP/M	B-Application
2.2	O
or	O
MER-DOS	O
(	O
compatible	O
with	O
TRSDOS	O
2.3	O
)	O
.	O
</s>
<s>
It	O
was	O
a	O
separate	O
specialized	O
computer	O
based	O
on	O
the	O
Z80	B-General_Concept
processor	O
@	O
2MHz	O
with	O
2	O
KiB	O
EPROM	O
and	O
1	O
KiB	O
RAM	O
.	O
</s>
<s>
The	O
8255	B-Device
chip	O
was	O
used	O
for	O
communication	O
with	O
the	O
Meritum	B-Device
computer	O
.	O
</s>
<s>
It	O
could	O
work	O
with	O
Meritum	B-Device
II	O
floppy	O
drive	O
unit	O
.	O
</s>
<s>
In	O
this	O
configuration	O
,	O
the	O
Meritum	B-Device
II	O
computer	O
with	O
a	O
connected	O
disk	O
drive	O
would	O
act	O
as	O
a	O
server	O
,	O
student	O
computers	O
were	O
based	O
on	O
Meritum	B-Device
I	O
.	O
</s>
<s>
Elwro	B-Device
800	I-Device
Junior	I-Device
was	O
later	O
selected	O
for	O
schools	O
.	O
</s>
<s>
The	O
Meritum	B-Device
network	O
variant	O
was	O
not	O
produced	O
,	O
only	O
experimental	O
units	O
were	O
made	O
.	O
</s>
