Gizmo5

Gizmo5 (formerly known as Gizmo Project and SIPphone) was a Voice over IP communications network and a proprietary freeware soft phone for that network. On November 12, 2009, Google announced that it had acquired Gizmo5. On March 4, 2011, Google announced that the service would be discontinued as of April 3, 2011.

The Gizmo5 network used open standards for call management, (SIP) and (XMPP). However, the Gizmo5 client application was proprietary software and used several proprietary codecs, including GIPS and Internet Speech Audio Codec (iSAC).

Gizmo Project was founded by Michael Robertson and his company SIPphone.

On November 12, 2009, Google announced that it had acquired Gizmo5 for a reported $30 million in cash. Prior to this acquisition, Gizmo5 had a working relationship with GrandCentral (now Google Voice) for years. Upon announcement, Gizmo5 suspended new signups until a Google relaunch. Google was also dogfooding a Google Voice desktop client based on Gizmo5, branded as Gizmo5 by Google.

On April 3, 2011 Google shut down Gizmo5 and recommended users to use Google Talk instead.

Gizmo5 was based on the Session Initiation Protocol and could interoperate with other SIP-based networks directly, including the public switched telephone network. The latter required the Gizmo5 service features CallOut and CallIn. CallOut was available at a fee, whereas CallIn and calls to other VoIP users were generally free of cost. Gizmo5 also used encryption () for network calls and worked well with Phil Zimmermann's Zfone security features.