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C > CENTRAL DATA  > 2650   


The 2650 was first reviewed in the US magazine Radio-Electronics, in the April 1977 issue.

This computer was supplied in assembled form with an Editor / Assembler. A 12K BASIC was also available on cassette tape or floppy if you had the HD interface.

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In 1977, I was interested in amateur radio and Morse code and wished to build a keyboard to transmit Morse. Designs I had seen seemed to use a lot of ICs and I thought that it would be better to use one of these new-fangled microprocessors which I could program to send Morse and also use for other things.

Most microprocessor board designs seemed to require a separate terminal with even more ICs. However I remembered seeing a design in Radio-Electronics which combined the terminal and processor on the one board and should be cheaper to build.

So I copied the three articles from the April - June issues and read them thoroughly. I did not have enough money to buy all the parts at once, but I ordered the bare circuit board in December 1977 and it took me a year and about $500 to obtain all the parts. Thirty years later I suppose that would be equivalent to about $5000, which seems a lot of money for a computer with 768 bytes of memory! At the time, I recall saying to a friend that I had spent the year building a money sink.

Learning to program took a while and hand assembling with its need for counting relative offsets in hexadecimal led to me counting other things as . . . 8, 9, A, B, bugger . . .

I took me until May 1979 before I first used the 2650 system to send Morse code, but alas, I found that using two hands and the large keyboard on the operating desk were inconveniences which led me to go back to my old keyer.

But I found many other entertainments associated with the computer, building homebrew dynamic memory, NRZ recorder and floppy disk controller.

I later used a Tandy Color Computer before succumbing to the PC. However I later started using PIC16C84s as I remembered having so much fun with assembler with the 2650.

73 VK7RO

Wednesday 3rd December 2008
Richard Rogers (Australila)

I just bought the board, and injected the RF into the innerds of a TV, Got a keyboard, and got going with the machine code. I remember I stole display memory for program execution and took advantage of half bytes that were identical. I think it could automatically adapt to speed of the morse code, but I can''t remember if it was for receiving for transmitting... I''d like to get one again. Pitched it.

Thursday 4th January 2018
Peter Wotherspoon (Peterborough, Ontario Canada)

The Ami/WinArcadia emulator is the only emulator of this machine. You can get it from

Monday 2nd February 2009
James Jacobs (Canberra/Australia)
Emerson Arcadia 2001 Central


NAME  2650
TYPE  Home Computer
YEAR  1977
CPU  Signetics 2650
SPEED  1.18MHz (Xtal of 14Mhz divided by 12), later increased to 4.73Mhz with improved 2650 chips
RAM  2 KB (up to 32 KB)
TEXT MODES  80 chars. x 16 lines
COLORS  Monochrome
I/O PORTS  S-100 BUS, one parallel input port
PRICE  2650 board : $275
16 KB RAM board $289
24 KB RAM board $395
32 KB RAM board $475
Editor/Assembler $20 - Basic language $20

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