It's no accident that Apple chose a yellow icon for its walkie-talkie feature. I dug out my old (2002ish) Nextel with PTT (push to talk). It was all the rage back then... :
Motorola Yellow Cell Phones and Smartphones for sale | eBay
Do Nextel Walkie Talkies Still Work? (December 2023)
That annoyed BEEP BEEP from NEXTEL phones in the 90s (sound in comments) : r/nostalgia