I worked for Zebra Systems, Inc. in Woodhaven NY which was one of the main Timex/Sinclair
mail order houses.
My memory of the story is that Timex submitted a Spectrum with an NTSC RF Modulator to the
FCC and it failed the approval process. They then redesigned the Spectrum to meet FCC
standards, and while they were at it, added new features they felt the American market
needed.
That resulted in the TS-2068 Computer.
I have one of the prototype North American Spectrum units, as well as an Interface One and
Cartridge drive.
Al Hartman
Keansburg, NJ