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.
I spent many years programming and selling Shelton Sig-net they were designed by a guy called Chris Shelton of Shelton Instruments and they had CPM operating system. I used to program in Microsoft Compiled Basic and the biggest system I sold was a 48 user to Sunseeker Travel in Huddersfield in 1988. Originally it was one processor per screen all connected to a hard disk using sheltons purpose designed ringring system which was a bus between the processors and the z80 running the hard disk. Rhodime made in scotland in 7/14/21 megabytes that formated down to 5/10/15 MB. I have lots more information if your interested.
Sunday 1st July 2018
gary smith (United Kingdon)
It would be nice if you could send us some pictures of this rare system!
Saturday 5th June 2010
I Currently own one of these- without a diskette drive. The case to this machine is easy to remove because it has a little button you can push to unlock it. I''ve been trying to find out who made my system$ and this is the same exact model. thanks old-computers.com!
Saturday 5th June 2010
BUILT IN LANGUAGE
Depending on the video terminal used
Z80-A (or B)
64 KB to 128 KB (one-processor system)
A graphic card was available - Features unknown
SIZE / WEIGHT
2 x Serial RS232, 1 x Parallel Centronics
BUILT IN MEDIA
1 to 4 200, 400 or 800 KB 5'' floppy disc drives
Built-in power supply unit + one power supply per card
Optional 7 MB hard disk (£3300 + £600 for the controller)
Basic version (200/2) about $2900 + video terminal