 Sinclair 's licensing agreement with Timex enabled the American company to produce three clones or offshoots of Sinclair machines for the US market . These were the Timex Sinclair 1000 , Timex Sinclair 1500 ( both variants of the ZX81 ) and the Timex Sinclair 2068 ( a variant of the ZX Spectrum ) . The TS1000 was launched in July 1982 and sparked a massive surge of interest ; at one point , the Timex phoneline was receiving over 5 @,@ 000 calls an hour , 50 @,@ 000 a week , inquiring about the machine or about microcomputers in general . It was virtually identical to the ZX81 save for re @-@ branding and the addition of an extra 1 KB of memory , making for a grand total of 2 KB . In the five months following the TS1000 's launch , the company sold 550 @,@ 000 machines , earning Sinclair over $ 1 @.@ 2 million in royalties . 
