{"id":625,"date":"2012-01-24T22:36:55","date_gmt":"2012-01-24T21:36:55","guid":{"rendered":"http:\/\/www.anyma.ch\/blogs\/research\/?p=625"},"modified":"2016-02-11T07:07:31","modified_gmt":"2016-02-11T06:07:31","slug":"4-channels-of-video-over-ethernet-cable","status":"publish","type":"post","link":"https:\/\/www.anyma.ch\/blogs\/research\/2012\/01\/24\/4-channels-of-video-over-ethernet-cable\/","title":{"rendered":"4 channels of video over ethernet cable"},"content":{"rendered":"

Update:
\nATTENTION The cable pairs in CAT6 cable are not wired this way !!!! This circuit works for small distances but on longer runs channel 2 talks into channel 3 and vice versa.
\nDidn’t redo my boards, did just cut and rewire wrong traces. <\/p>\n

Cable pairs are (1,2) \/ (3,6) \/ (4,5) \/ (7,8)<\/strong><\/p>\n

\n

This is nothing new and has been done in the security CCTV world for years, but I’m still surprised it was so easy.
\nThursday we have to make a multicamera capture of the premiere of the Fribourg Opera – in Fribourg’s brand new theatre – which is huge – and we just don’t have enough cables to get all the signals out of the venue into a quiet place where I can do the mixing.<\/p>\n

But they do have kilometers of CAT6 cabling, patchbays everywhere, and even some Extron BNC-RJ45 adaptors to send video throughout the building. But why use one adaptor and one cable per camera – there’s 8 wires in a ethernet cable. It should be possible to send 4 symmetric video signals, each on a twisted pair..
\nUsing an inverting opamp to make a symmetric signal doesn’t sound too terrifying, and a differential amplifier on the other side to get an asymmetric out of it again, neither.
\nSo last night after returning from the theater I fired up EAGLE and sketched a 4 channel BNC video to RJ45 converter, and surprise: It seems to work really well.
\nDead simple. Just beware that instead of the LM833 I’m using MAX4392 opamps which are much better suited for video (pinout is the same, I simply can’t find the symbol for it in EAGLE)<\/p>\n

I tested one channel today at the venue through around 100m of CAT6 and the picture was perfect. Can’t wait to see all four cameras tomorrow..<\/p>\n

The transmitter:
\n<\/h3>\n

Two channels shown in closeup
\n\"\"<\/a><\/p>\n

The receiver<\/h3>\n

\"\"<\/a><\/p>\n

EAGLE files<\/h3>\n

Very quickly hacked together – should have done other things today and it has to work tomorrow:
\n4BNCToRJ45_20120124.zip<\/a><\/p>\n

Pictures<\/h3>\n

I’m really in a hurry, this has to work tomorrow… no time to build a case…
\n\"\"<\/a>

\"\"<\/a>

Transmitter<\/p><\/div>\"\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Update: ATTENTION The cable pairs in CAT6 cable are not wired this way !!!! This circuit works for small distances but on longer runs channel 2 talks into channel 3 and vice versa. Didn’t redo my boards, did just cut and rewire wrong traces. Cable pairs are (1,2) \/ (3,6) \/ (4,5) \/ (7,8) This […]<\/p>\n","protected":false},"author":2,"featured_media":632,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"_links":{"self":[{"href":"https:\/\/www.anyma.ch\/blogs\/research\/wp-json\/wp\/v2\/posts\/625"}],"collection":[{"href":"https:\/\/www.anyma.ch\/blogs\/research\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.anyma.ch\/blogs\/research\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.anyma.ch\/blogs\/research\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.anyma.ch\/blogs\/research\/wp-json\/wp\/v2\/comments?post=625"}],"version-history":[{"count":4,"href":"https:\/\/www.anyma.ch\/blogs\/research\/wp-json\/wp\/v2\/posts\/625\/revisions"}],"predecessor-version":[{"id":740,"href":"https:\/\/www.anyma.ch\/blogs\/research\/wp-json\/wp\/v2\/posts\/625\/revisions\/740"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.anyma.ch\/blogs\/research\/wp-json\/wp\/v2\/media\/632"}],"wp:attachment":[{"href":"https:\/\/www.anyma.ch\/blogs\/research\/wp-json\/wp\/v2\/media?parent=625"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.anyma.ch\/blogs\/research\/wp-json\/wp\/v2\/categories?post=625"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.anyma.ch\/blogs\/research\/wp-json\/wp\/v2\/tags?post=625"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}