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       #Post#: 221--------------------------------------------------
       Timex TS 1500 and Microdigital TK85
       By: IngDuenas Date: November 22, 2016, 10:01 pm
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       Both Timex and MIcrodigital came up with "enhances" versions of
       the ZX81. Both computers were basically a ZX81 with a rubber,
       Spectrum like, keyboard and built-in 16Kb RAM. They behaved like
       a ZX81 altough the TK85 had an expanded ROM which included a
       higher than originall baud rate for cassette storage options
       handled by USR calls. The TK85 could saveverify and load in
       4800Bps (as read in the manual). I've got some conflicting
       information stating that the baud rate was 1500bps but if I
       recall correctly, it did not sound like 1500 as the pitch was
       very high... and very unreliable... These "extra" features will
       cause some ZX81 software to be unable to run but I own about 50
       tapes for the ZX81 and none of them actually failed on the TK,
       the computer also sported a joystick port in a form of a five
       PIN DIN jack.
       The TS 1500 had less chips than the original ZX81 while the TK85
       had a discrete ULA resulting in many more chips, please see
       pictures below. I had both of them and I did attach them a TS
       RAM expansion for a glorious 32Kb of RAM (it took forever to
       booth, or seemed like that back in the day).
       All and all, the quality of both products was quite high at the
       time and when compared with the ZX81 both computers were clearly
       winners.
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