Ooma

Founded in 2004 by Andrew Frame, a former Cisco engineer. The pitch inverted the usual subscription: buy the Ooma Telo box once, wire it between your broadband and an ordinary phone, and then call within the US with no monthly fee — just taxes and surcharges. Actor Ashton Kutcher was brought on as an early public face.

The company went public in 2015 and still works the seam between home and small business, where VoIP meets plain SIP handsets. It's a niche that Nextiva and the larger cloud phone systems have mostly left alone.