This is the AlphaTantel from 1981, and it's not exactly known if it ever made it into production.
Certainly search engines and even magazines of the day know nothing about it. It was made by Tantel in Ely, Cambs,
at the same address that ultimately spawned the Oric-1 because Tantel were a side project of
Dr Paul Johnson's Tangerine, aka the company that brought us the Microtan65 single board computer.
The original Tantel was a keypad driven Prestel adapter that plugged into your telly via the built in RF modulator,
and into your phone via the supplied GPO jack plug. This is assuming you'd had the GPO around to add a socket to your house wiring
of course - all phones of the day were hardwired into the PSTN and owned by the GPO themselves. The Tantel could also drive a cassette
recorder to save your expensive pages for later and featured a printer port for hard copies.
Someone at Tantel thought that wasn't enough though. Prestel also allowed a crude type of email known as 'messaging'
where you could 'chat' with other Prestel users as long as you knew their phone number. If you were both online it was fairly instant
too, if not it would be held until you next dialled in. Cue the addition of a tiny keyboard to the adapter. Also cue people in 2020
asking 'where's the RETURN key?'. There isn't one because Prestel was at heart numeric only so the 'end of transmission' key was #,
the good old hash. ('Pound' for my US readers).
The reason it's not known if these ever made production is twofold. First is they were seemingly never
advertised apart from a tiny text advert in PCW in 1981. The Micro Tantel by comparison got full page adverts and reviews. The second
reason is the chap whose first job at Tantel was to recode the Micro's ROM to add support for this keyboard doesn't think they were ever
produced in volume.
Currently this one's not very well and just produces screen of blocks. I think it has a RAM issue however, because it
draws the TANTEL logo and dialling menu and prompts 'PLEASE DIAL' before filling the screen, a possible error not caught because a chip has
failed. There are 3 different types of RAM present. Screen RAM is via a pair of 2114 DRAM chips and works OK. Next is an MCM6810P SRAM
chip which could possibly be for configs, numbers to dial etc. Lastly is an MCM51L01C45 CMOS SRAM chip which I think is for the page store,
and it's also this one which may be faulty since the unit acts the same way whether it's present or not. More work required.