From: utzoo!decvax!microsof!uw-beave!jim Newsgroups: net.video Title: Re: Monitor as well as television? Article-I.D.: uw-beave.276 Posted: Wed Jan 5 10:26:53 1983 Received: Thu Jan 6 05:26:09 1983 References: ihuxm.145 The big problem is that most modern TVs use a hot chassis. This means that chassis ground, which is one of the two wires going into the baseband video circuit, is connected to one side of the AC line. This is considered a shock hazard. The RF modulator is a kind of AC isolator. For VCRs I don't think the RF modulator limits you very much because the signal coming out of the VCR is so poor (please no flames). But for video games and home computers this a big loss. It has even convinced some computer manufacturers to limit their screens to 40 characters wide, or less. The ironic part is that an RF modulator is a whole lot more expensive than the better alternative, opto-isolators. An RF modulator is about $50, an opto-isolator is more like $5. An opto-isolator has more bandwidth than any monitor. The problem is that it would have to be built in to the TV, and would add a whole $5 or so to the manufacturer's cost. The RF modulator doesn't cost the TV manufacturer anything (but it does cost you $50). I keep hoping that the new FCC rules about TV interference will make RF modulators so expensive that there will be pressure on the TV makers to put opto-isolators in their TVs and provide baseband video inputs, but so far I've seen no evidence of this.