Oi Selects Ditech Networks’ Voice Processing Platform with VQA™ for Delivering Exceptional Voice Quality

VQA to Serve a Growing Base of 12.6 Million Customers in Brazil

Mountain View, California, February 22, 2007 - Ditech Networks Corporation (NASDAQ: DITC) today announced that Oi, a leading mobile telecommunications company in Brazil, has selected its Quad Voice Processor (QVP) platform with Ditech’s flagship Voice Quality Assurance (VQA™) software for delivering ultra-clear voice quality across its GSM mobile network. The Ditech platform will enable Oi to significantly improve users’ calling experience while increasing network capacity. For Ditech, Oi represents an important addition to a rapidly growing list of GSM mobile operators that are using its solutions to improve call quality and maximize network capacity.

“We chose Ditech Networks as our voice quality partner because of its unique VQA technology, which enables us to successfully meet two critical challenges,” said Mr. Antonio Parrini Pimenta, Network Director of Oi. “Ensuring high voice quality is essential to building customer loyalty. At the same time, we must be able to scale network capacity without compromising quality. The Ditech VQA solution enables us to meet our customers’ expectations for excellent call quality and build on that loyalty to attract new customers—while minimizing infrastructure changes and capital expenditures.”

Oi is one of Brazil’s leading GSM carriers, serving more than 12.6 million subscribers in 16 Brazilian states in the country’s north, northeast and southeast regions. Oi offers integrated solutions, comprising local voice services, long distance, mobility, data communications, service provision, and Internet services. Deployment of the high-density Ditech QVP platform in the Oi GSM network will enable the company to deliver consistently clear, end-to-end communications across the GSM network without the need for overbuilding the infrastructure.

“We are pleased that Oi has selected our VQA solution to enhance voice quality in its mobile network,” said Tim Montgomery, president and CEO of Ditech Networks. "Exceptional voice quality is one of the keys to higher customer satisfaction. VQA will enable Oi to cost-effectively deliver outstanding wireless service throughout Brazil."

About Ditech Networks

Ditech Networks supplies voice processing equipment for telecommunication networks around the world. Ditech Networks' solutions incorporate advanced voice processing, Session Initiation Protocol (SIP), and security technologies delivered on carrier-grade scalable platforms to enhance the delivery of communications services over mobile, Voice over IP, and wireline networks. Ditech Networks' customers are premier network operators including Verizon Wireless, Sprint/Nextel, Orascom Telecom, and others that collectively serve more than 150 million subscribers. Ditech Networks is headquartered in Mountain View, California. For more information, visit www.ditechnetworks.com.

About Oi

Oi is a company of Telemar Group and owner of the first GSM network in Brazil with 4.1 thousand Radio Base Stations (RBSs) and 12.6 million subscribers. The GSM standard for mobile telephony has been adopted by 82% of the owners of cellular phones in the planet according to The GSM Association. The GSM technology allows for access to high speed internet, Location Based Services (LBS), data transmission, video, pictures and music via cellular.

Oi began operations in June 2002, operates today in 16 Brazilian states (offering GPRS coverage as well) including: Rio de Janeiro, Espírito Santo, Minas Gerais, Maranhão, Pará, Amazonas, Amapá, Roraima, Bahia, Sergipe, Alagoas, Pernambuco, Paraíba, Rio Grande do Norte, Ceará e Piauí.