TS-940 Brochure
I have scanned all 12 pages of the original TS-940 sales brochure. You will notice that it is called a Trio and not Kenwood. This was done purely for the UK market before Kenwood Japan acquired the right to use that name on it's product in UK and applied to other Kenwood products such as stereo equipment as well.

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From the late 60's or early 70's, I think, Lowe Electronics based in Matlock Derbyshire were the sole UK importers for what was then called Trio amateur radio equipment. During the 1980's equipment bearing the Kenwood name began to appear in the UK having been imported either from Europe or America at more favourable prices. At some point in the mid to late 1980's Kenwood stopped using the Trio name and it became impossible to tell if a particular Kenwood radio was either a 'grey import' or a true UK market model. As the sole importer Lowe electronics issued each radio it sold, either directly or through one of it's appointed distributors, with a 'passport to service'.
It is quite an interesting document, showing the original purchaser and date of purchase. If anybody knows G4BXR he might be interested to learn that his TS-940 is still going strong and living in Thailand.
Original Lowe Electronics passport to service
Copy of the IF-10B interface instruction manual pp1-7 & 23
Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 23
Copy of the IF-232C manual
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I have pulled both EPROM's from my TS-940S and saved the code in Intel hex format.
Right click and select 'Save Target As...' to download TS-940S firmware version JA4 (That's what it says on the chip)
Download IF-10B firmware
My email address is hs0zed followed by the @ symbol then qsl dot net