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1977: Telmac 1800

Telmac 1800 was a simple CDP1802 system introduced here in Finland around 1977.  It was designed by Osmo Kainulainen, who built his own computer using RCA CDP1801, that he already knew from his job. RCA gave him a small monitor program to use with it (which one?). The design was published in a magazine as "Hobby Computer" and more or less started the personal hobby computing age in Finland by soon turning into Telmac 1800 kit, which used CDP1802. It was a lot like COSMAC VIP, but not exactly. Telmac has been the first touch to hobby computers for many people here.

Telmac 1800 was manufactured by Telercas Oy, which was also local distributor of RCA components. Telmac was delivered as a kit and gained quite big success. Some 2000 units were manufactured and sold during four years. It was estimated during 1979 (Prosessori-lehti/Vesa Valtonen), that  60-70% of hobby computers in Finland were Telmacs. 500 units were also ordered to Sweden.

Telmac 1800 Kit Telmac 1800 with CRT expansion


One of the first computer clubs in Finland, 1800 User's Club, was also established mainly around Telmac users.

Telmac was programmed using machine language, CHIP-8 and M-2. Especially CHIP-8 became popular. A lot of nice games were made using CHIP-8, which is a very small interpreter (less than 512bytes), but still has functionality to handle video screen, key input and sound (sort of).

There was also a CRT extension available later, that came with tiny BASIC on tape.

The basic kit had 2k RAM and as far as I know a 512-byte monitor ROM. Video (1861, NTSC!) generated 64x192 pixels, but was very often used with 64x32 or 64x64 as that made more square dots on screen. Programs could be saved to a tape recorder.

One problem with original Telmac 1800 was, that it used the 1861 'Pixie' video chip, which generates NTSC signal. Finland is PAL country, so some problems did occur.

Telmac 1800 was followed by Oscom Nano and  Telmac 2000.

"Hobby Computer" layout

Telmac 1800 Extension Connector

Telmac 2000 history in unclear to me. It was an improved version over 1800, but I don't know who actually designed that one and how mane were made.

2000 had PAL version video chip (1864) with color also supported and more RAM, board could hold 16k bytes.

Telmac 2000 PCB layout (several versions existing?)

A bit later (1982?) a more professional TMC-600 also followed. It run CDP1802 at 3.58MHz, had 9k RAM and 20k ROM (SBASIC). CRT controller generated color ASCII text, capable of 24 rows of 20 or 40 characters according to the manual.

Telmac TMC-600



[Hobby computer]

[CRT controller OK 10478}

[CRT controller OSM-200]



[Telmac2000 Kokoamisohje]

[Telmac 2000 Käsikirja]

[Telmac 2000E Käsikirja]

[TMC-600 Käsikirja]



some day...



Looking for more information on Telmacs!


Last modified: May-09

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