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M > MERA-ELZAB > Meritum     


This Polish computer was first introduced in fall 1983. As pretty much every sophisticated piece of hardware from the Eastern Block, it was copied from a western computer. The ROM is based on the TRS-80 model II, so the Meritum can be considered as a TRS-80 clone. It was mainly used in schools and is considered as the precursor of the polish computing industry as it was the first computer to be produced in Poland.

In fact the Meritum is not entirely Polish but rather a miracle of the eastern block industry : the keyboard and case is polish, disk-drives made in Hungary (some sources say Germany) and memory from Bulgary. 8'' disk-drives are said to be the Robotron K6500 ones...

The keyboard is quite special : left, right and down keys are situated on the right part of the keyboard whereas the up key is placed at the opposite left side !! Quite practical... Much weirder, two keys are blank !!

The Meritum has 64 graphic symbols. The Basic takes 12k of the 14k ROM. It is a Tandy Basic modified to use polish letters (Model 2). Some keyboards have Cyrillic letters for the Soviet union instead of the Latin alphabet. The system uses a U880D microprocessor which is a East-German clone of the Z80.

There are two models, the Meritum model 2 having more memory (48k RAM) and higher resolutions than the model 1. It can be connected to external disk-drives and have a built-in disk controller. It can use polish alphabetical signs and has a parallel port.

The Model 1 which had no graphical resolution (only semi-graphic symbols), no colors, small memory and very high price, was not very popular and was considered obsolete even before being marketed !

A Meritum III was released and shown on Poznan fair 1986, but apparently wasn't produced.

Among planned but never created accesories were: network interfaces ( this was actually produced for the II model ), and a expansion graphics processor that would in these days be called nothing more than a graphics accelerator :) Unfortunately, Mera was forced to suspend the productions of Meritums in favor to computer terminals etc. The whole assembly staff of the Meritum line was five people, and East Germany could not meet the demands for the 5,25" disk drives that were needed for the Meritum II. Meritum was abandoned, as it couldn't compete with private imports of C64 and Atari computers.

If you find some info or know more about the Meritum computers, please mail us.



"A Meritum III was released and shown on Poznan fair 1986, but apparently wasn''t produced." - it''s not true. I have one. Elwro probably produced about 100 computers. I suppose still exist about 5-6 pcs.

Thursday 6th September 2012
Grzegorz (Poland)

I have this computer with improved ROMs - experimental serial interface based network management software is added and memory is expanded to 64K. Not always Bulgarian - sometimes there were Soviet. I heard about a few ROMs in this computer:
First one, asks "MEMORY SIZE", it''s the first one.
Next one, asks "OBSZAR PAO", it''s the most common one.
My version asks "MEMORY SIZE" and displays "OETO-POL.SL.NET-BASIC" or something like that - it''s an experimental networking system, maybe one shown in technological exhibition in Bulgaria (?Plovdiv?). Network extensions are started by NET command.
Another version tries to boot from floppy and if it''s impossible jumps to monitor. I don''t know anything about it except I have a photo of it running (from internet auction).

Saturday 24th September 2011

This piece of hi-tek computing wasn't really popular/widely spread in Poland. Even in 1983 it was deemed out-of-date and the main decision to produce it was probably because of the ease of constructing it in the communist Poland at that date :( Remember all commie countries were blocked from western technologies those days. Nevertheless certain laws were bent and we had western Z80 with a changed name etc.

Sunday 27th August 2006
Thomsonicus (Poland)


NAME  Meritum
TYPE  Home Computer
ORIGIN  Poland
YEAR  Model 1 : 1983
Model 2 : 1985
KEYBOARD  QWERTY full-stroke keyboard, 57 keys, arrow keys
NMI, CTRL, SHIFT (x 2), ENTER, CLEAR, BREAK. Two keys are blank
CPU  U880D CPU (east-german Z80 clone)
SPEED  2,5 Mhz
RAM  Model 1 : 16 KB
Model 2 : 48 KB (up to 64 KB)
ROM  14 KB
TEXT MODES  32 chars x 16 rows
GRAPHIC MODES  Model 1 : 64 / 32 x 16, 128 x 48
Model 2 : 64 / 32 x 16 (semigraphic mode), 256 x 192 (4 shades of grey), 512 x 192 (monochrome)
COLORS  Model 1: monochrome
Model 2: at least 4 colors
SOUND  1 channel
SIZE / WEIGHT  37.2 (W) x 23.8 (D) x 7.8 (H) cm
I/O PORTS  Power Supply (DIN5), Paralell interface (DB26), Serial Interface (DIN5), Tape-recorder (DIN5, 500 baud)
Model 2 has an external disk drive connector (DB26)
OS  Model 2 : MER-DOS, CP/M 2.2
POWER SUPPLY  +5v/2.5A, -5v/0.1A, +12v/0.2A
PRICE  160,000 Zloty (Poland, 1984)



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