MUMBAI: TV networks in the US, Fox, NBC Universal and CBS, have separately sued satellite broadcaster Dish Network to battle the latter?s ad-skipping DVR service AutoHop service that allows consumers to skip television ads.

At the same time, Dish has taken a step to protect its new service by filing a lawsuit against Fox, NBC, CBS and ABC, although ABC has not sued Dish. The network provider sought a "declaratory judgment" that its AutoHop feature is legal arguing, "viewers have been skipping commercials since the advent of the remote control."

Since 10 May, Dish has been advertising a digital video recorder service called ?Primetime Anytime? that gives consumers access to the last eight days of prime-time programming from the four major broadcast networks - ABC, NBC, CBS and Fox - sans the commercials.

Fox released a statement saying that Dish?s service may "destroy the fundamental underpinnings of the broadcast television ecosystem." It added that the wrongheaded decision requires Fox to take swift action in order to aggressively defend the future of free, over-the-air television.

NBC also released a statement explaining that advertisements generate the revenue that makes it possible for local broadcast stations and national broadcast networks to pay for the creation of the news, sports and entertainment programming. The statement further said that Dish did not have the "authority to tamper" with the ads from broadcast replays on a "wholesale basis for its own economic and commercial advantage".

According to CBS, this service takes existing network content and modifies it in a manner that is "unauthorized" and "illegal" making it a clear violation of copyright law.

According to TV ratings and research provider Nielsen, about 40 per cent of the 115 million television households in the US have a DVR. About 8.4 per cent of all TV viewing among adults aged 18 to 34 last year constituted watching programs on DVR which is an increase from about 7.9 per cent in 2010.