Verizon is to shut down its VoiceWing Internet-based phone service from March 31.

In a letter to customers, the outfit said that it wanted to focus on other technologies.  VoiceWing used a small adapter that allowed them to place calls by connecting a phone to a broadband Internet line.

The Voice over IP market has been taking a battering in the US thanks to problems with call quality and patent law suits from phone companies. Cable companies, meanwhile, have used similar technology to successfully introduce their own phone services.

Already Deltathree which ran back-end services for VoiceWing has seen its stock delisted from the Nasdaq and is fast running out of cash. Meanwhile Verizon has released what it calls the "The Hub," which is a multifunction touch-screen home phone that connects to a broadband line.

It also plans to release a VoIP service on its fibre-optic network.