I gather from the preceding posts that the use of CAT5 for the transport of unbalanced audio and video has become somewhat popular. I am surprised that you've all have had as much success as your posts suggest.

CAT5 and other UTP communications cable was intended for use with equipment capable of rejecting any induced common-mode noise by employing a balanced differential receiver or balun transformer. Consumer A/V gear is not properly equipped. Furthermore, video signals (composite, s-video, all common component formats) rely on 75 ohm impedance matching from source to cable to receiver. To use CAT5 to transport audio and video in the manner you've described is a real gamble.

That's not to say that CAT5 can't be succesfully and reliably used for A/V. There are several manufacturers offering receiver/transmitter products that employ either passive balun transformers or active electronics to balance/unbalance the signals and perform the necessary impedance matching. When used with such products, CAT5 can be used to cary signals over very long runs with no appreciale signal degradation. Otherwise, I wouldn't be at all surprised were even a short run of CAT5 to exhibit any of a number of EMI/RFI noise problems. Maybe not at first, but perhaps a few weeks after installation, when a CBer or shortwave radio buff drives by...

For short runs of S-video, I suggest sticking with either siamesed 75 ohm coax designed specifially for the purpose, or two parallel runs of high quality RG-6. (By the way, if anyone knows of a way to neatly terminate discrete coax to s-video, I'd be grateful to hear it. Maybe some sort of pre-fab adapter?)

For long runs using UTP, check out these product lines:
[Link: extron.com]
[Link: kramerelectronics.com]

This message was edited by M_Bruno on 08/09/03 18:59.