Comcast, the leading U.S. cable operator, said on Monday it will integrate its e-mail and voice messaging services in a new Web-based communications center called SmartZone.

In a bid to boost customer loyalty with free add-on services, SmartZone will enable Comcast's 12 million high-speed Internet subscribers to access their voice mail and e-mail from the same online platform, with instant messaging and an interactive address book.

The company's 3 million digital phone subscribers will also be able to use the service.

Comcast believes services like SmartZone will strengthen its relationship with subscribers who may be tempted by offers from satellite television operators, or from telephone companies that are also selling video and Internet services.

Comcast will not be charging for the new service, continuing a strategy of offering subscribers extra services such as free video-on-demand to encourage loyalty. It currently allows subscribers to view up to 95 percent of its video-on-demand programming for free.

In the last two years, cable operators have been able to reverse customer losses by bundling television, phone and high-speed Internet access in competitively priced packages.

Comcast created SmartZone in partnership with Hewlett-Packard Co., Zimbra, a specialist in messaging software and Plaxo, an online address book service.

Comcast is hoping to eventually integrate SmartZone with its television service and its Pivot mobile phone service, which is in the early stages of being introduced in partnership with Sprint Nextel Corp. in some regions.