# USB-C Female to Micro USB adapter, possible? Safe? **URL:** \ **Category:** Factual Questions\ **Created:** [March 8, 2019, 3:56pm UTC](https://boards.straightdope.com/t/usb-c-female-to-micro-usb-adapter-possible-safe/830774 "2019-03-08T15:56:28Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![RitterSport](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rittersport/32/6326_2.png) [@RitterSport](https://boards.straightdope.com/u/RitterSport)\ **Post date:** [March 8, 2019, 3:56pm UTC](https://boards.straightdope.com/t/usb-c-female-to-micro-usb-adapter-possible-safe/830774/1 "2019-03-08T15:56:28Z")
My next phone will have a USB-C adapter. Currently, my phone and all of my devices are Micro USB (e-book, head phones, Bluetooth speakers, etc.). So, I have tons of Micro cables everywhere – I plan on buying a bunch of Micro female to C male adapters from Monoprice. I know the new phone will charge slowly, etc. However, there will be times when the available cable is a USB C cable, and I want to be able to go the other way. Monoprice doesn’t seem to have any, but I found something on Amazon. However, since USB C chargers can be plugged in either was, is there a device safety issue? Seems like half the time, power will be ground and vice versa from the perspective of the Micro USB device. Is that why Monoprice doesn’t carry them? They seem much more rare, and yet, over time as all my cables change to C, I’ll still have to charge my devices. Thanks! ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [March 8, 2019, 4:07pm UTC](https://boards.straightdope.com/t/usb-c-female-to-micro-usb-adapter-possible-safe/830774/2 "2019-03-08T16:07:31Z")
[**The Wrong Cable Can Fry Your Devices**](https://www.howtogeek.com/353410/3-problems-with-usb-c-you-need-to-know/) > [@](#): > > This is the most pressing thing new USB-C users need to learn about. In previous generations of USB, a cable was pretty much a cable. Sure, if you plugged a USB 1 cable into a USB 2 port, it might not work—or at least, work well—but that was the extent of it. People mostly didn’t need to think about which cables to buy. > > That’s not the case with USB-C, and ignoring this could cost you dearly. > > The problem is specific to cables with the older USB-A connector on one end and the new USB-C connector on another. (USB-A, if you didn’t know, is the traditional USB plug we’ve all been using for years.) But, USB-C devices (and cables) support faster charging than USB-A. So, for example, if you plug a USB-A device (like a cell phone) into a USB-C port using one of these cables, the phone may draw too much power, frying your phone, USB-C port, or even computer. > > Now, to be fair, properly-made cables can have resistors inline to prevent this from happening. The trouble is, it can be really hard figuring out which cables are good and which are not, unless you’re buying from a reliable vendor that provides good technical specifications. > > Research how to buy a USB-C cable that won’t damage your devices. ---
**Author:** ![RitterSport](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rittersport/32/6326_2.png) [@RitterSport](https://boards.straightdope.com/u/RitterSport)\ **Post date:** [March 8, 2019, 5:45pm UTC](https://boards.straightdope.com/t/usb-c-female-to-micro-usb-adapter-possible-safe/830774/3 "2019-03-08T17:45:02Z")
> [@Jasmine](#): > > [**The Wrong Cable Can Fry Your Devices**](https://www.howtogeek.com/353410/3-problems-with-usb-c-you-need-to-know/) It’s not that I doubt your source, but this doesn’t make sense to me – USB -A could always deal with a variety of power supplies and power draws. My understanding is that the connected device would negotiate with the power supply to limit how much power it will get. How can that not be the case with USB-C, where the variety of power drawn is larger by an order of magnitude? This didn’t exactly answer my question – is it possible to make a safe USB-C to Micro-USB adapter? ---
**Author:** ![misling](https://avatars.discourse-cdn.com/v4/letter/m/3ab097/32.png) [@misling](https://boards.straightdope.com/u/misling)\ **Post date:** [March 8, 2019, 7:40pm UTC](https://boards.straightdope.com/t/usb-c-female-to-micro-usb-adapter-possible-safe/830774/4 "2019-03-08T19:40:48Z")
1. It is possible to make such a connector. 2. It is possible for that connector to be safe. It is also possible for that cable to be unsafe. 3. It is often not possible for the end user/buyer to tell whether the cable they are considering is in fact one of the safe ones. ---
**Author:** ![Cleophus](https://avatars.discourse-cdn.com/v4/letter/c/a88e57/32.png) [@Cleophus](https://boards.straightdope.com/u/Cleophus)\ **Post date:** [March 8, 2019, 7:52pm UTC](https://boards.straightdope.com/t/usb-c-female-to-micro-usb-adapter-possible-safe/830774/5 "2019-03-08T19:52:21Z")
> [@RitterSport](#): > > My next phone will have a USB-C adapter. Currently, my phone and all of my devices are Micro USB (e-book, head phones, Bluetooth speakers, etc.). So, I have tons of Micro cables everywhere – I plan on buying a bunch of Micro female to C male adapters from Monoprice. I know the new phone will charge slowly, etc. > > However, there will be times when the available cable is a USB C cable, and I want to be able to go the other way. Monoprice doesn’t seem to have any, but I found something on Amazon. > > However, since USB C chargers can be plugged in either was, is there a device safety issue? Seems like half the time, power will be ground and vice versa from the perspective of the Micro USB device. Is that why Monoprice doesn’t carry them? They seem much more rare, and yet, over time as all my cables change to C, I’ll still have to charge my devices. > > Thanks! [https://www.amazon.com/Anker-Adapter-Transfer-Resistor-MacBook/dp/B01AHKYIRS](https://www.amazon.com/Anker-Adapter-Transfer-Resistor-MacBook/dp/B01AHKYIRS) USB-C polarity is handled by active electronics inside the connector and the symmetrical arrangement of the pins. There is no effect on the downstream device. ---
**Author:** ![RitterSport](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rittersport/32/6326_2.png) [@RitterSport](https://boards.straightdope.com/u/RitterSport)\ **Post date:** [March 8, 2019, 8:00pm UTC](https://boards.straightdope.com/t/usb-c-female-to-micro-usb-adapter-possible-safe/830774/6 "2019-03-08T20:00:45Z")
> [@Cleophus](#): > > [https://www.amazon.com/Anker-Adapter-Transfer-Resistor-MacBook/dp/B01AHKYIRS](https://www.amazon.com/Anker-Adapter-Transfer-Resistor-MacBook/dp/B01AHKYIRS) > > USB-C polarity is handled by active electronics inside the connector and the symmetrical arrangement of the pins. There is no effect on the downstream device. Thanks, but those are the exact opposite of what I’m looking for. My initial concern came about because neither Monoprice nor AmazonBasics seem to make what I’m trying to get. ---
**Author:** ![Cleophus](https://avatars.discourse-cdn.com/v4/letter/c/a88e57/32.png) [@Cleophus](https://boards.straightdope.com/u/Cleophus)\ **Post date:** [March 8, 2019, 8:36pm UTC](https://boards.straightdope.com/t/usb-c-female-to-micro-usb-adapter-possible-safe/830774/7 "2019-03-08T20:36:44Z")
Sorry, I misinterpreted. The opposite type of adapter is officially frowned upon by the USB Implementer’s Forum because there’s too many invalid combinations possible with a female USB-C adapter, but there’s no physical reason it can’t be made and some vendors do make one. They are theoretically no different from a USB-C male to microUSB-B male cable. It could be made to work OK if you are careful to manually check the power supply requirements of the device with regard to power supply capacity, but nonetheless some USB-C power supplies may refuse to deliver power because it’s not seeing the expected power negotiation signals. The article Jasmine linked is talking about something else. There were low-quality cables floating around that could not handle high-current USB Power Delivery applications and did not contain the signaling resistor wiring (note that they are not “current limiting” resistors in the proper electronics sense of the term) to indicate they were not fully compliant with USB-PD requirements. ---
**Author:** ![RitterSport](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rittersport/32/6326_2.png) [@RitterSport](https://boards.straightdope.com/u/RitterSport)\ **Post date:** [March 11, 2019, 11:25am UTC](https://boards.straightdope.com/t/usb-c-female-to-micro-usb-adapter-possible-safe/830774/8 "2019-03-11T11:25:56Z")
> [@Cleophus](#): > > Sorry, I misinterpreted. The opposite type of adapter is officially frowned upon by the USB Implementer’s Forum because there’s too many invalid combinations possible with a female USB-C adapter, but there’s no physical reason it can’t be made and some vendors do make one. They are theoretically no different from a USB-C male to microUSB-B male cable. It could be made to work OK if you are careful to manually check the power supply requirements of the device with regard to power supply capacity, but nonetheless some USB-C power supplies may refuse to deliver power because it’s not seeing the expected power negotiation signals. > > The article Jasmine linked is talking about something else. There were low-quality cables floating around that could not handle high-current USB Power Delivery applications and did not contain the signaling resistor wiring (note that they are not “current limiting” resistors in the proper electronics sense of the term) to indicate they were not fully compliant with USB-PD requirements. Sorry my reply is so long in coming. Thanks for this! I’ll avoid those specific adapters. I’ve already run across a USB-C oddity – we just got a Nintendo Switch, which appears to use a USB-C charger, but my friend’s Pixel 2 couldn’t use it.