DATAMATH  CALCULATOR  MUSEUM

Additional Pictures 

 

The printed circuit board (PCB) of the original Spelling B
makes use of the TMC0272 single chip microcomputer and
an external TMC1984. Probably a TMS1000 microcomputer.

The PCB of a later Spelling B makes use of the TMC0274
single chip microcomputer and an external TMC0355
128kBit "Speech-ROM". The buzzer is connected at the left.

 

A closeup picture of the TMC0355 (CD2602) ROM.

The printed circuit board of the early Spelling B sold in UK
is identical with the original "US" Spelling B.
It misses the buzzer, too.

This  Spelling ABC sold in UK makes again use the TMC0274
single chip microcomputer and an external TMC0355 (CD2602) 128kBit "Speech-ROM".

`

 

The printed circuit board of the German Spelling ABC is
identical but uses another code in the external TMC0355 (CD2607) 128kBit "Speech-ROM".


If you have additions to the above article please email: joerg@datamath.org.

Joerg Woerner, February 13, 2005. No reprints without written permission.