Why are the earphones for my portable music systems not compatible with my cell phone?
Maybe its because cellphone earphones include a microphone, which requires a more complicated jack.
My phone has a seperate jack for just headphones, not hands-free, because its an MP3 player too, so no mic. While I have no evidence to back this up, it seems like cell phone accessories are a big business, and the lack of compatability is there to sell more junk. I cannot really see how the phone has a more sophisticated connection than my home stereo.
Well, there are standard sizes, and the cell phone is a 2.5mm jack while the standard music headphone jack is 3.5mm (1/8").
I imagine it may just be the same reason that headphones use a 1/8" plug rather than 1/4" like your home stereo: because it’s easier to fit the jack somewhere.
Some phones, including mine, do use a standard 3.5mm jack for their headsets. For me, it’s the same jack for earphones (which has two signals), the headset (which has 4), and a TV-Out adapter (which has three).
I can (almost) guarantee you that the variance in connector types is mostly so that the phone manufacturers can sell more things to their customers.
I don’t think it’s that sinister. Things just get designed without much thought for how the consumer might want to use them. The designers and engineers pick a connector that fits the space and electrical requirements. The fact that it’s different than a another product’s jack isn’t very important to them. At least there is some standardization in audio jacks - the situation is much worse for power jacks.
My bleepin’ phone (Windows Mobile, so MP3 player and etc.) has a mini-USB connector for the headphones. I had to rip apart the supplied in-ear phones and wire for a normal jack so I could use real headphones on the plane.
I still haven’t found such an adapter commercially, nor any phones with the mini-USB connector.
Is the same connector also used for USB? Using the same connector for both purposes helps minimize the size of the device. The iPod Shuffle takes the same approach but the other way around: the 3.5 mm headphone jack is also used for USB and power (battery charging). But of course, with these approaches you need either a non-standard headphone or a non-standard USB cable.
No, as an engineer I can tell you that the marketing and business plan decision between using proprietary connections (to sell more custom accessories) or using open standards (to make the product cheaper) has usually already been decided before an engineer ever sees the product.
It depends completely on the particular business model the company is pursuing. The good companies out there will respect technical feedback from their engineers, but it usually starts as a top-down push where engineers are told what to develop.
I can tell you that engineers would much rather use something standard and universal if it can be made to work, there is nothing we hate more than reinventing the wheel just so that proprietary crap can also be peddled to support a marketing specification.
I’m an engineer, and I can assure you that what I said happens all the time…
Yes, it’s the same port for sync/charge as well as the headphone. They give you a special “Y” cable if you want to do both.