ZX81

The ZX81 was Sinclair Research's follow up to the successful ZX80. The ZX81 had an improved 8K ROM and could display a picture and execute a program simultaneously, at the expense of processing performance. Sinclair established a relationship with Timex in the UK, who manufactured the ZX81 for Sinclair in their Scottish plant. The eventually lead to Timex licensing the ZX81 for manufacture in the USA under the Timex Sinclair brand. The Timex Sinclair 1000 was the first of several machines Timex licensed from Sinclair for the US market. Several of Timex's later machines were enhancements from Sinclair's design and dramatically improved on the originals.