EDIT: Actually Bluetooth is probably what you're looking for. Invented in 1994, but not really widely used until the last 15 years or so. I would assume mostly because audio quality was so shit for so long. Further, Bluetooth uses Frequency-hopping Spread Spectrum, which was actually developed in World War II.

I always considered cell phones (now just "phones) to be one of those things. In the 1980's they had massive honking mobile phones, and in the 90's fancier people had "car phones," but actual common cell phone use didn't really take off until the 2000's in the USA and really only exploded in 2007, post-iPhone.

I had a land-line until like 2005.

It's also interesting to note that the mobile-phone happened quicker in Japan. They had car-phones and a 1G network in 1979 and their first mobile handset came out in 1985, two years after Motorola. Also, texting was booming in Japan by the late 90's/early 2000's while Americans had barely just started, and were often using phone plans that only allowed for a limited number of texts. Texting adoption in the US was slow for a long time due to this.