Digital Group
Digital Group Computer was an early computer kit company where you could buy it assembled or build it yourself. Building it yourself was a great way to learn about computers and Digital Group had very excellent documentation. The bus was design allow you to change CPUs (8080,Z80 and 6800) and all your perpherial would continue to function. A neat trick! However they had their own bus which wasn't S100 which meant you had to buy cards from them.
This was the first computer kit. At that time, you could only buy a completed computer which was Altair. My friend Frank Nargie bought the kits, soldered the components on the circuit boards and built a complete working computer. When he moved, he gave the his entire collection which I photographed.
What is so amazing about the kits was the documentation. It iwas a complete course on how everything works. So you are not just assembling a computer but you are learning how it works.