NTL, which has refused to comment on the news, has been planning a partial flotation of the business, which provides broadcast services for ITV, Channel 4 and Channel 5.
A spokesman confirmed that NTL had been looking at other ways of realising the value of its broadcast business, which during the first quarter of this year generated £57m and 40% of group's underlying earnings.
Crown Castle International, a rival transmission business, is understood to be eyeing the business, however it has not yet opened negotiations with NTL.
Analysts believe the outlook is good for the business, partly because it can lease its transmission towers to mobile phone operators, which need to establish networks for third-generation mobile phones.
Meanwhile, NTL has appointed former BSkyB marketing chief David Thatcher to the position of managing director for the east and south-east of the UK.
Thatcher left BSkyB in 2000 to join Mviva, the Wap portal owned by AOL and Carphone Warehouse.