Newsgroups: comp.dcom.cabling
Subject: Re: S-Video to Twisted Pair keystone adapters
References: <[email protected]> <[email protected]> 
[email protected] (Dmitri(Cabling-Design.com)) writes:

> glen herrmannsfeldt wrote:
> 
> > Video signals usually have a DC offset, so won't go through
> > a transformer.
> 
> They do make S-Video as well as baseband composite video passive baluns.

True. 

> Never looked inside one though. Should be transformers as no external
> power is required. Works fine.

This kind of baluns are typically mede either with a full 
transformer (75 ohm to 100 ohms) or using or using common 
mode choke apprach (sometimes called current mode balun, 
does balacing well at higher frequencies, pass DC, but 
does not do impedance matching).  

> In OP's case I think the problem must have been the lengths. S-Video yields
> the least distance and in this un-balanced version should not have been
> more than 20-30 feet, if even that. Unless this was done for the benefit
> of laptop users having S-Video outputs, I would switch to composite video
> (with RCA connectors) that usually yields 75 ft or more on CAT5E. Both
> manufacturers make RCA keystone jacks as well.

-- 
Tomi Engdahl (http://www.iki.fi/then/)
Take a look at my electronics web links and documents at 
http://www.epanorama.net/