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title, categories, types, origins, years, cpus, params
title categories types origins years cpus params
SHELTON INSTRUMENTS Sig-Net
Computers
Professional Computer
United Kingdom
1981
Z80-A
name image company company_name specs forum_thread oc_id source
Sig-Net /media/museum/photos/shelton_signet_system_1.jpg /companies/shelton-instruments SHELTON INSTRUMENTS
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NAME Sig-Net
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MANUFACTURER Shelton Instruments
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TYPE Professional Computer
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ORIGIN United Kingdom
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YEAR 1981
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BUILT IN LANGUAGE None
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KEYBOARD Depending on the video terminal used
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CPU Z80-A (or B)
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SPEED 4 MHz.
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CO-PROCESSOR None
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RAM 64 KB to 128 KB (one-processor system)
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ROM 4 KB
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GRAPHIC MODES A graphic card was available - Features unknown
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SOUND Beeper
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SIZE / WEIGHT Unknown
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I/O PORTS 2 x Serial RS232, 1 x Parallel Centronics
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BUILT IN MEDIA 1 to 4 200, 400 or 800 KB 5'' floppy disc drives
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OS CP/M
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POWER SUPPLY Built-in power supply unit + one power supply per card
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PERIPHERALS Optional 7 MB hard disk (£3300 + £600 for the controller)
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PRICE Basic version (200/2) about $2900 + video terminal
791 810
url date
https://web.archive.org/web/20230528100258/http://www.old-computers.com/museum/computer.asp?c=810 2023-05-28

Shelton Instruments were the people behind the original design of the Nascom 1. They were based in London.

Sig-Net was a totally new concept, whereby a series of boards - processor, interface, memory, etc. - were interconnected by flexible wires.

Each board had its own power supply and many variations of computer could be evolved from the basic system components.

The Sig-Net 200 series computer had a number of these modules housed in an enclosure that can have two integral floppy disc drives. The system came with 64 KB of RAM and up to 4 KB of ROM. There were two RS232 interfaces and a 4-channel real-time clock.A hard disk controller could be connected on-board.

The system was indefinitely expandable, even to a multi-processor system, using Sig-Net modules. CP/M 2.2 operating system came with the computer allowing the vast CP/M library of software to be used.