Axiom Home Page Forums General Discussion Technical Questions 3.5 mm jack wiring

I was going to purchase 3.5MM keystone adapter so that I could plug the digital out (AC-3 SPDIF) from my computers soundcard into the wall and hear it through my stereo. There are 2 conductor and 3 conductor 3.5MM jacks, I don't know which I need or how they should wired. Does anyone know this?

OK...You really have to clarify this a bit. My understanding is that 3.5mm is an analog interface, so I'm not sure I understand the interface between that and your SPIDF (digital) interface.....and the wall???? If you are talking about going from the 3.5mm to your analog (rca) interfaces, then you probably need the simple stereo 2 conductor plugs. If you are looking to do more than 2-channel audio, then you'll need to do this either 3 or 4 times depending if you are doing analog out 5.1 or 7.1.

As you can tell from my response, I'm a abit confused about what you're asking, so you may want to expound on it a bit. If I can't help, there is bound to be someone here that can.

TD, a connector's a connector; they're not necessarily analog or digital (ok, ok, optical's virtually always digital). Sound cards use little connectors on them because space is at a premium. That said, I don't know the answer to the question, either!

My soundcard has a bunch of jacks in the back and they're all the exact same size. According the Audigy2 user manual the seventh one is a digital out jack for "6 channel or compressed AC-3 SPDIF for connection to external digital devices or digital speaker systems".

This site: http://www.cablestogo.com/product_list.asp?cat%5Fid=2709 sells 3.5MM keystone jacks that looks like the jacks on the back of my soundcard. They are for IR emitters and it states that you can "Connect a 3.5mm cable from your PC sound card and play MP3s throughout your distributed audio system. 3.5mm Modules are easy to connect to UTP cable; simply push the terminal and insert the wire."

They're sold as 2 conductor or 3 conductor jacks. I wanted to know how many wires do I need and is there a particular way to wire them like you have to do with RJ-45 jacks for ethernet. I'm not concerned about switching to RCA plugs, just the wiring from jack A to jack B.

Im not really sure what kind of setup your using or anything but, if its an analog you have the ground, and left and right channels. the two wire would be for mono. But i really am lost about what your doing so if im talking about something completely different, well that alright. lol

If I understand correctly you're just trying to connect from the sound card into your receiver, right ? Not sure about the "wall" reference... I think that refers to pushing the sound out across an in house network (probably over power wiring) but that's a different format.

Which are you trying to do ?

If you just want sound card out going into your receiver you need to (a) connect 2 of the 4 pins on that digital/analog jack to a coax cable with RCA plug on the other end, and (b) set your card to "digital outputs only" to put the S/PDIF signal onto the jack.

Here's some good blurb about how to do it... the link has lots of posts, this looked like the most knowledgeable one. There seems to be hot debate re: whether a mono "3.5mm to RCA jack" is the way to go, or whether you need a "4 pin 3.5mm to dual RCA jack" cable. The good news is that everything seems to come from Radio Shack

One caveat -- this only seems to work for playing DVD/CD, sounds like the Creative cards won't put game audio out on the S/PDIF interface. Not 100% sure of that though...

"The Audigy/Audigy 2 or any creative SB with the digital output requires a MONO 3.5mm to coax cable (or RCA, same bit different name). The best way to connect this is by getting a 3.5mm MONO to coax converter then plugging a coax or RCA video cable (yellow) from the converter to the Coax input of any reciever (use the yellow not the white or red as coax should be no less than 75ohm for quality reasons).
You must select digital output only from your card options...also if you are using a DVD programme make sure you select SPDIF so your reciever decodes as opposed to the PC, this may require an upgrade with most DVD software players but is well worth it (if you have a good reciever to decode)
I have an Audigy connected to my Sony STRDA5000ES reciever using the above solution, before I was using 5.1 direct (3 x 3.5mm stereo to 6 RCA) and the volume was very low, now it is digital (SPDIF) the volume is unbearably loud where before it was quiet. The recievers blue S-master pro light comes on also when playing DVD from the PC indicating it is recieving a raw signal...hope this helps, I was looking for ages and finally decided to look at the online Audigy manual that clearly shows the configuration for connectivity to external recievers "

http://forum.ecoustics.com/bbs/messages/5/1656.html

Ken - You're right. When I was talking about the 3.5's being analog, I was talking about when they are audio outputs....which I thought was a correct line of thinking. However, I had forgotten that during my early searches for audio cards that some manufacturers do SPDIF via 3.5 plug and not optical/coax. I was left with the same question as the poster......so I just moved on to another card that had an optical ouput.

Yeah, that sounds like the right way to go. Seems like some of the sound card vendors offer S/PDIF output but it's at TTL level instead of the <1V needed to drive coax. The idea is good (lets you converter to either optical or coax) but it means you need a converter every time.

I'm fairly sure that the Creative cards are coax level but the manual sure uses a lot of words without actually telling you.

Well I typed a bunch of stuff and pressed continue and then lost all of it because I wasn't connected.

For those that didn't fully comprehend what I was trying to do I'll reiterate. I wanted to plug a cable from the back of my sound card into a 3.5mm jack or a RCA jack in the wall behind my computer. The jack would be connected to an identical jack in the family room behind my stereo where and additional cable would connect it to my receiver's digital coaxial input. I've read the messages from ecoustics.com and I'm still not sure if or when this would get sound from an Audigy2 soundcard's digital out to come out of all speakers in a 5.1 speaker setup. Here is one part that I wasn't sure if it were true or not "use the yellow not the white or red as coax should be no less than 75ohm for quality reasons". I thought that the compposite video cable was the same as the left/right audio cables and that it made no difference if you used the yellow for audio and/or the red for video. I also didn't understand what the different segmented parts of a 3.5 mm plug were used for. I'll just have to experiment and see if I can get it to work.

Thanks for your help.

Ahh, now we understand. In geek-speak :

- adapter as required to go from digital out on the sound card to standard digital coax

- long cable (how long ?) from adapter to AV receiver, with a couple of wall jacks along the way

Some moderately priced cables use coax for video and wire pairs (or cheaper crappier coax) for audio.

The trick with the 3.5mm plug is that the jack is used for either analog or digital outputs (not both together). Analog needs 2 pins per channel, so two channels per jack needs a 4 pin plug/jack. The card contains some switches so that either the analog OR digital signals go the the jack, and the digital signals have "signal" wired to 2 pins and the "ground" wired to the other 2 pins.

It sounds as if a 2 pin plug can be put into a 4 pin jack and will not short anything out, so in theory you can stick a 2 pin plug into the jack, switch to digital outs, and everything should work.

For people who worry about shorting out their card (like me) the advice is to get a 4-pin 3.5mm to 2xRCA cable so you can put a 4-pin 3.5mm into the card. The only trick then is to make sure you get the and have the right signals going to the right part of an RCA jack -- it seems the card is wired up so that normal adapters work well, but only one of the two RCA jacks will work properly.

Confused ?