If you’re annoyed by having to carry around a dongle to use your old wired headphones with a new phone or tablet deprived of a headphone jack, things could be worse: That dongle might turn out to be only decorative.
That’s not what you’d expect from sales pitches for such recent no-headphone-jack devices as Google’s Pixel 3 and Pixel 3 XL phones and Pixel Slate tablet or Apple’s new iPad Pro. Get an adapter to plug into the USB-C port on these devices, plug your old headphones into the adapter’s 3.5-millimeter jack, there is no step three.
But as buyers have learned, some USB-C headphone adapters don’t work with some of these portable gadgets. That’s not due to random technological misery, but a mismatch in where the digital audio coming from an app on the device gets turned into the analog output needed by regular headphones.
“As device manufacturers started to remove the 3.5mm audio jack, there was no uniformity in the next standard in audio output,” said Steven Lomeli, a product manager at the electronic-accessories vendor Monoprice, in an e-mailed statement. “Some manufacturers thought the conversion should occur on the adapter and others thought it should occur on the device itself.”
So if a phone didn’t include that digital-to-analog converter (DAC), the adapter would need to provide its own--but some cheaper ones leave that out.
Further, some devices vendors compounded the problem by opting for custom circuitry that not all adapters could cope with.
“Many manufacturers were simply trying to be first to market with proprietary adapter designs that only worked with their own products” explained Rahman Ismail, chief technology officer of the USB Implementers Forum trade group, in an e-mail conversation. “Contrary to popular belief, routing analog signals over USB-C wires is quite complex – there are many different ways to route this signal.”
(The Lightning ports on Apple’s iPhones don’t suffer from this incompatibility since Apple controls the entire Lightning specification. But Apple’s latest iPhones, among its most expensive ever, also no longer come with a headphone-jack-adapter in the box.)
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Finding an adapter that includes its own digital-analog converter and should work is not so simple.
“Look for the adapter’s USB-IF Certification Logo or its certification status in the product manual,” Ismail advised, noting that the USB Implementers Forum only certifies those with built-in digital-audio conversion.
Monoprice’s Lomeli said that firm held off on shipping its own adapter until it determined that it was safest to ship one with a DAC built in. But its description of that $10 dongle doesn’t call out USB-IF certification (although customer reviews do attest to its compatibility with such phones as the OnePlus 6T and the Google Pixel 2).
In light of all this confusion, the single most attractive feature on Samsung’s new Galaxy S10 series of phones may be their traditional headphone jack.
This article originally appeared on USA TODAY: Why a USB-C headphone adapter can’t amount to jack