3 ms·
This is called balanced input/output. TRS connectors are also quite common, especially for interconnects. I find TRS/XLR combi sockets [0] used for this purpose
by friendzis 8y ago
This is called balanced input/output. TRS connectors are also quite common, especially for interconnects. I find TRS/XLR combi sockets [0] used for this purpose fascinating :)
Third wire does not collect interference in a balanced line. Instead, voltage signalling balanced line uses one ground and two signal lines of opposite polarity and input is difference between these two signal lines. Induced interference is more or less the same on both signal lines, therefore cancels out. At a quick glance this article [1] seems to explain this without delving into electronics. Some differential lines (e.g. RS-485, popular in industrial automation) use current signalling thus requiring two wires per signal.
[0]: http://www.cliffuk.co.uk/products/combijacks/combijacks.jpg http://www.cliffuk.co.uk/products/combijacks/combijacks.jpg
[1]: http://www.aviom.com/blog/balanced-vs-unbalanced/ http://www.aviom.com/blog/balanced-vs-unbalanced/
- tomn 8y agoIt gets even stranger: https://en.wikipedia.org/wiki/Star_quad_cable https://en.wikipedia.org/wiki/Star_quad_cable
- blattimwind 8y ago> Some differential lines (e.g. RS-485, popular in industrial automation) use current signalling thus requiring two wires per signal. Virtually all high-speed digital communication uses differential signalling.
- friendzis 8y agoAgree on that, but all high speed interconnects I know use voltage signalling.
- blattimwind 8y agoThat's orthogonal to differential or single ended, but typically the transmit side uses some form of current steering; it just goes well with it. E.g. PCIe transmitters are HSCL, which is a form of current steering that gives the receiver exactly the voltages it needs to see at nominal currents and termination values.