Comcast Corp.'s blind TV executive Tom Wlodkowski says the company's "talking TV guide" for the visually impaired will go live on the nation's largest cable-TV system by Dec. 1.

The talking guide, still in its beta phase, can be accessed by Xfinity subscribers on the company's X1 set-top boxes.

There are 5 million X1 set-top boxes in American homes and Comcast is switching out older boxes for X1s throughout its cable-TV franchise areas.

With about 22 million Xfinity TV subscribers, 600,000 to 700,000 of those could be classified as blind or visually impaired, based on national statistics.

The talking guide voices the current TV listings, on-demand listings and DVR functions.

Comcast announced in 2013 that it was developing the talking guide. Wlodkowski, vice president for accessibility, heads the project and works out of a special lab in the Comcast Center to develop products for those with disabilities.

He recently demonstrated the talking guide. The guide mostly worked as advertised, though it had a glitch in the movies section. Brian Roberts, Comcast's chairman and , announced that the talking guide would be released to the public at a conference in Silicon Valley on Wednesday afternoon.