USB to USB Type-C Adapter: Getting the Direction Right
Half of all adapter mistakes are direction mistakes. Buy the male end and the female end the wrong way round and nothing connects, no matter how good the adapter is.
Quick Answer
Decide which device provides the socket and which provides the plug. An adapter that turns a USB-C socket into a USB-A socket is different from one that turns a USB-A socket into a USB-C socket. For phone or tablet host mode you need an OTG capable adapter in the correct direction, and for charging you need USB-C at both ends.
Gender Combinations
| Adapter | Plugs into | Gives you | Typical use |
|---|---|---|---|
| USB-C male to USB-A female | A USB-C port | A USB-A socket | USB-A peripherals on a new laptop |
| USB-A male to USB-C female | A USB-A port | A USB-C socket | USB-C cables on an old host |
| USB-A male to USB-C male | Both ends as plugs | A connection | Device to host, needs correct roles |
| USB-C male to USB-C female | A USB-C port | An extension | Reach, with caveats |
| OTG adapter | A phone or tablet | Host capability | Keyboards, drives, controllers |
Host Mode and OTG
What OTG does
It tells a portable device to act as a host, so peripherals can be attached. The adapter usually ties an identification pin to ground to signal this.
Which devices support it
Most Android phones and tablets do. Support is less predictable on other platforms.
Power limits
A phone can only supply limited current. Bus powered drives often fail; a powered hub solves it.
Data and charging at once
Rarely possible with a simple adapter. Adapters that claim both use a splitter arrangement and often charge slowly.
What Each Direction Supports
| Function | Through a USB-A port | Through a USB-C port |
|---|---|---|
| USB 2.0 data | Yes | Yes |
| USB 3 data | Only if adapter is wired for it | Yes, if cable and device support it |
| Power Delivery | No | Yes, with an e-marked cable |
| Alt Mode video | No | Yes, on supported hosts |
| Host mode | Only on OTG capable hosts | By role negotiation |
Real-World Applications
- Using a USB-C SSD on an older desktop.
- Connecting a USB-A mouse to an ultrabook.
- Attaching a keyboard to a tablet for typing.
- Giving a phone access to a memory card reader.
Related Guides
For the speed limits, read USB to USB-C adapter. For multi port expansion, see USB-C port hub. For laptop use, start with multiport adapter for laptop.
FAQ
Which direction do I need?
Identify which device has the socket and which has the plug, then match. Most mistakes happen here.
Can an adapter add a port and charge at the same time?
Only with a hub that has a dedicated charging port. A simple adapter cannot do both well.
Does OTG work on every phone?
Most Android devices support it. Check the specification for other platforms.
Is a USB-C to USB-C adapter safe?
Generally yes, but it can interfere with Power Delivery negotiation, so prefer a full cable.