Salford-based Insight secured the awareness-raising brief after a four-way pitch.
Newspoint PR, which had previously held the account, did not repitch, according to Voice4IP head of marketing Maria Goggin.
Insight account director John Butters reports to Goggin. Agency MD Chris Warham will also oversee the account.
Warham said: 'We will be positioning Voice4IP as a leader in the VoIP space, and making the business case for the technology.'
The firm, a wholly owned subsidiary of AIM-listed Netservices, was launched in January.