The hidden “code” inside 2-XL toy’s space age noises

Do you remember the 2-XL toy?

2-XL (2-XL Robot, 2XL Robot, 2-XL Toy) is an educational toy robot that was marketed from 1978–1981 by the Mego Corporation, and from 1992–1995 by Tiger Electronics. 2-XL was the first “smart-toy” in that it exhibited rudimentary intelligence, memory, gameplay, and responsiveness. 2-XL was infused with a “personality” that kept kids focused and challenged as they interacted with the verbal robot. Learning was enhanced via the use of jokes and funny sayings as verbal reinforcements for performance. 2-XL was heralded as an important step in the development of toys, particularly educational ones. 2-XL won many awards, and Playthings, a toy industry magazine, placed 2-XL on its 75th anniversary cover as one of the industry’s top-ten toys of all time.

John Graham-Cumming’s blog discusses hearing RTTY or FSK in the audio stream.

FSK means “frequency shift keying”. It’s a way of sending data that uses two levels (0 or 1, or mark or space in the jargon). Data is encoded in some format (e.g. Baudot code or ASCII) and then sent using those two levels as audio or radio. One such radio format is RTTY which I messed around with in the past when sending up a high-altitude balloon.

I grabbed an audio file version of the clip of 2-XL and fed it into Fldigi to see if I could get an instant decode. No such luck. But I shoved the file into Audacity and took a look at the spectrum and there are two distinct peaks.

John went ahead and turned this into a stream of 1s and 0s, assume that the upper frequency is 1 and the lower 0.

Check out the decoding mystery in the blog here.


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