Sonim next generation super-tough Push-to-Talk 'BOLT' phones exclusive to Bell
Push-to-Talk: Nextel Is Still the One to Beat - Bloomberg
Slideshow: Motorola Pushes 'Push to Talk' | WIRED
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... :