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Inside a Speak & Spell

SpeaknSpell78.jpg (79273 Byte)Texas Instruments introduced in the year 1978 the famous Speak & Spell educational toy. Shortly after the invention of the synthesizer technology to reproduce human speech with tuned voices stored in ROM's the Speak & Spell took the world in a storm. Not counting the thousands and thousands of children using their red toy the Speak & Spell voice can be heard on countless electronic dance records like Kraftwerk’s 1981 Computer World album. Not satisfied with the stored voices the experimental composer and instrument maker Qubais Reed Ghazala took a Speak & Spell apart and rewired it. He calls this process circuit-bending, and the result of these accidental short-circuits and redirected signals make the Speak & Spell produce disturbingly twisted and nonsensical noises, the electronic equivalent of a machine speaking in tongues. The most famous appearance of the Speak & Spell is in the movie „E.T. - The Extra-Terrestrial“, where E.T. phones home on a modified toy.

In our opinion enough reasons to discover the inside of a Speak & Spell.

Speak & Spell, Version 1

The original version of the Speak & Spell could be easily recognized with the 40 round buttons keys instead the later flat membrane keyboard.

Inside a Speak & Spell produced between the years 1978 and 1980 you'll find 4 important components:

• The huge printed circuit board (PCB) with the 
   speech synthesizer technology
• The keyboard composed of two TI-1200 keyplates 
   with 20 keys each
• The loudspeaker with a small transformer
• An last but not least 4 C-sized batteries

From higher interest for most of us is the printed circuit board.

This is the first view of the PCB after removing it from the housing. In a next step we bend the two TI-1200 keyboards away. SpeaknSpell_78_KBD.jpg (74996 Byte)
This is the component side of the whole electronics. Clicking on the PCB will open a new page on your browser and you may switch between the description and the full screen picture. SpeaknSpell_78_PCB.jpg (205637 Byte)

 
Please notice: The PCB above is not identical with the PCB of the left Speak & Spell!

Speak & Spell, Version 1 - With Jacks

Later models of the Version 1 received two added jacks for an external power supply and head phone.

This is the component side of the whole electronics. Please notice the Speech-ROM's with the CD2303 and CD2304 designation,an abbreviation of Custom Data indicating the British English voices stored inside. SpeaknSpell_UK_PCB.jpg (188730 Byte)

 


Speak & Spell, Version 1 - Japanese Edition

In Japan the jack for the head phone is accessible from the front and the connector of the external power supply placed slightly different to the standard model.

Speak & Spell, Version 2

The later version of the Speak & Spell uses a flat membrane keyboard instead the button keys. The inside view is similar.

On a first glance the new Speak & Spell looks cheaper than its predecessor. The basic layout is identical but a lot of cost recuction optimization was done by the engineers of Texas Instruments:

• The printed circuit board (PCB) is much smaller
• The hidden keyboard uses a much simpler technology 
   but this one is much more resistant against toddlers
• The loudspeaker is coupled directly to the electronics
• The batteries are unchanged


From higher interest for most of us is the printed circuit board.

This is the normal view of the PCB. Famous "Circuit-Bender" Qubais Reed Ghazala uses this view for the diagrams and pictures on his website. SpeaknSpell_PCB1.jpg (169095 Byte)
This is the component side of the whole electronics. Clicking on the PCB will open a new page on your browser and you may switch between the description and the full screen picture. SpeaknSpell_PCB.jpg (122173 Byte)
This is the component side with the locations of the parts marked. Clicking on the PCB will open a new page on your browser and you may switch between the description and the full screen picture. SpeaknSpell_PCB_2.jpg (147543 Byte)

Speak & Math and Speak & Read

SpeaknSpell.jpg (65621 Byte)SpeaknRead.jpg (72103 Byte)SpeaknMath.jpg (53235 Byte)buddy.jpg (74271 Byte)The Speak & Spell and its two sibblings, the yellow Speak & Read and the grey Speak & Math  use identical electronics with some changes in the software and different solid State Speech™. 
The blue Buddy on the right most position is the rare German edition of the Speak & Spell.



Microcontoller: The microcontroller is derived from the TMS1000 series and adopted to control both the keyboard, the display and to feed the speech synthesizer. 

• Speak & Spell uses a TMC0271 which interprets as TMC0270, ROM-Code 1. 
• La Dictιe Magique and Grillo Parlante uses a TMC0270/CD2702 which interprets as TMC0270, ROM-Code 2.
• Early Speak & Math uses a TMC0270/CD2704 which interprets as TMC0270, ROM-Code 4. 
• Speak & Read uses a TMC0270/CD2705 which interprets as TMC0270, ROM-Code 5.

Later Speak & Math uses a TMC0270/CD2708 which interprets as TMC0270, ROM-Code 8. 

Speech Synthesizer: The Speak & Spell series uses with the TMS5100 / TMC0280 the first one-chip LPC speech synthesizer. Later refinements to the Speak & Spell chips resulted in the TMS5110, TMS5200 and TMS5220 Voice Synthesis Processors for commercial products.

• Speak & Spell, Read and Math uses a TMC0281 which interprets as TMC0280, Version 1. 
• Sometimes it is called a TMC0280/CD2801 which interprets as TMC0280, Version 1.

Speech ROM: Speech data is stored in a 128k ROM chip with the designation TMC0350.

• The original Speak & Spell introduced in the year 1978 and the first models of the new edition from 1980 uses TMC0351 and TMC0352
   which interprets as TMC0350, ROM-Code 1 and 2.
• Later Speak & Spells - starting about the year 1981 uses TMC0350/CD2350 which interprets as TMC0350, ROM-Code 0.
   This is actually a double VSM (Voice Speech Memory) with 256k capacity.
• Speak & Read uses TMC0350/CD2394 and TMC0350/CD2395. Both are double VSM's
• Speak & Math uses TMC0350/CD2392 and TMC0350/CD2393, a set of double VSM's too.
• Speak & Math produced around the year 1985 and later  use TMC0350/CD2381 and TMC0355/CD2614, a double VSM and a single VSM.

 

Find a more detailed list of the VSM's here.

Additional Speech ROM: The Speak & Read populates the second Speech ROM to increase vocabulary.

Expansion Module: Plug-in modules increased vocabulary.

Printed Circuit Board: The PCB of the different Speak & Spell, Read and Math got a lot of redesigns during the production years. You'll locate a revision number on most PCB's near the Expansion connector. The table below gives a first correlation between the revision number and the date of manufacturing. 

Speak & PCB Code Revision Manufacturing code Est. date of manufacturing Speech ROM's
Spell (Original) 1033303-3 REV.G MTA-0879 year 1979 wk 08 TMC0351, TMC0352
Spell (Original) 1033303-3 REV.J RCI-4679 year 1979 wk 46 TMC0351, TMC0352
Spell (Original) 1033303-3 REV.J MTA-1680 year 1980 wk 16 TMC0351, TMC0352
Spell (Original) 1033303-3 REV.J PII-2780
Philippines
year 1980 wk 27 TMC0351, TMC0352
Spell (JP) (Original) 1033303-3 REV.J Japan   TMC0351, TMC0352
 Spell (Original) 1040672-1 REV. MTA-3180  year 1980 wk 31 TMC0351, TMC0352 
 Spell (UK) (Original)      RCI-3880  year 1980 wk 38 TMC0350 (CD2303), TMC0350 (CD2304)
Spell 1040675-2 REV.D MTA-4480 year 1980 wk 44 CD2394, CD2395
Read 1040675-2 REV.D MTA-4480 year 1980 wk 44 CD2394, CD2395
Spell 1040675-2 REV.G MTA-4680 year 1980 wk 44 TMC0351, TMC0352 
Maths 1040675-2 REV.G(ET) RCI-3481 year 1981 wk 34 CD2392, CD2393
Math 1040675-3 REV.J LTA-3781 year 1981 wk 37 CD2392, CD2393
Spell 1040675-4 REV.L ATA-4182 year 1982 wk 41 CD2350A
Math 1040675-4 REV.L ATA-3282 year 1982 wk 32 CD2392, CD2393
Spell (UK) 1040675-9 REV.AA RCI-3284 year 1984 wk 32 CD62175A
Spell 1040675-9 REV.AA ATA-4883 year 1983 wk 48 CD2350A
Spell 1040675-9 REV.AA LTA-1184,
LTA-3184
year 1984 wk 11  CD2350A
Spell (UK) 1040675-9 REV.AA RCI-0285 year 1985 wk 02 CD62175A
Spell 1040675-10 REV.AE LTA-0685 year 1985 wk 06 CD2350A
Grillo Parlante 1040675-10 REV.AE RCI-1485 year 1985 wk 14 CD62190
Spell (UK) 1040675-10 REV.AE RCI-2385 year 1985 wk 23 CD62175A
Math 1040675-10 REV.AE LTA-3985 year 1985 wk 39 CD2381, CD2614
Math 1040675-12 REV. AJ LTA-0386 year 1986 wk 03 CD2392, CD2393
Read 1040675-12 REV. AJ USA-166A year 1986 wk 16 CD2394, CD2395
Spell 1040675-12 REV. AJ USA-166A year 1986 wk 16 CD2350
Read 1040675-13 REV. AK USA-017A year 1987 wk 01 CD2394, CD2395
La dictee magique 110358/2    RCI-1687 year 1987 wk 16 CD2352
Spell 1040675-13 REV. AK USA-307A year 1987 wk 30 CD2350A
Read 1040675-13 REV. AL USA-107A year 1987 wk 10 CD2394, CD2395
Math 1040675-13 REV. AL USA-107A year 1987 wk 10 CD2381, CD2614
Spell 1040675-14 REV. AN USA-417A year 1987 wk 41 CD2350A
Grillo Parlante 110358-0012    RCI-1188 year 1988 wk 11 CD62190
La dictee magique 110358-0012    RCI-1188 year 1988 wk 11 CD2352
Spell 1040675-15     USA-198A year 1988 wk 19 CD2350A
Spell 1040675-15     USA-198A year 1988 wk 19 CD2350A
Grillo Parlante 1040675-15     USA-398A year 1988 wk 39 CD62190
Math 1040675-15   USA-268A year 1988 wk 26 CD2381, CD2614
Maths 1040675-15     USA-358A year 1988 wk 35 CD2381, CD2614
Maths 1040675-18    USA-2489 year 1989 wk 24 CD2381, CD2614
Spell (UK) 1040675-18   USA-2889 year 1989 wk 28 CD62175A
Spell 1040675-18   USA-2989 year 1989 wk 29 CD2350A
Spell (UK) 1040675-18   USA-0990 year 1990 wk 09 CD62175A
Spell (UK) 1040675-18   USA-1491 year 1991 wk 14 CD62175A


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

© Joerg Woerner, January 27, 2002. No reprints without written permission.