Terayon's ( TERN) shares rose sharply Monday after Cox Communications ( COX) said it would use its TJ715 cable modem on its network and make Terayon a preferred broadband vendor.

Cox said the first batch of TJ715 modems will be deployed at its Phoenix plant, the company's largest facility and a competitive market for residential broadband services.

Terayon's shares jumped 31% to $2.87 on the news.