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Raspberry Pi Production Delayed By Factory's Assembly Flub
nk497 writes "The first shipment of Raspberry Pi devices has been delayed, after the factory manufacturing the cheap educational computer used non-magnetic jacks instead of ones with integrated magnetics. The problem is already nearly fixed, but new jacks need to be sourced for subsequent shipments, so those could be delayed slightly. 'It's inevitable, isn't it — you're freewheeling along perfectly happily and then you get a puncture,' said spokeswoman Liz Upton, apologizing for the delay."
From the Raspi forums :
"It doesn’t mean no network connection at all on all devices, but this board has been designed for a magnetic jack. The magnetic bits mean better signal integrity, better filtering and shorter transmission distances for data."
"Magnetics refers to the presence of transformers and chokes which are used to isolate the Ethernet wires from the RaspPi’s power supply. and each other and probably to reduce high-frequency noise. Without them you would effectively tie the RX and TX signals together and probably turn the entire network into an aerial for Radio 2 reception."
As I stated in the other, non-annointed article and posted here, the magnetics are actually tiny transformers used to convert from differential to single-ended signals and to isolate. Additionally center taps can be used for PoE.
"The magnetics in question aren't to hold the connector in like those in a Mac power cord, but rather the tiny transformers that are required for Ethernet differential signal isolation/transformation."
Tiller's Rule: Never use a word in written form that you've only heard and never read. You will end up looking foolish.
I'm assuming that's the case here, and the magnets are providing filtering (given the cable's got a predominantly plastic and copper end it's not going to do much to hold it in place).
They're not magnets. They're tiny transformers and inductors that magnetically couple the signals while providing 1.5 kV DC isolation and some filtering against common-mode disturbances.
How do they work?