Micro-A to Micro-B: The Rare Pair
Quick answer / TL;DR: Short answer: micro-A is the host-role variant of the micro connector, distinguished by its shape and an extra ID pin. Micro-A to micro-B cables are used where a small device must act as host – some cameras, phones and industrial handhelds. They are uncommon: confirm the socket type on both devices before ordering, and expect limited local availability.
Micro-A is the host-side version of the micro connector: the same small shell, but with an extra pin that signals host mode. A micro-A to micro-B cable connects a tiny host device – a phone acting as host, a small camera – to a micro-B peripheral.
This is the rare-connector guide: what micro-A is, the devices that use it, and how to source a cable that most shops do not stock.
What Micro-A Is
| The connector | The role | The difference |
|---|---|---|
| Micro-B | Device | Standard small plug |
| Micro-A | Host | Extra pin, different shell |
| Micro-AB | Either | Accepts both |
The AB socket accepts either plug and decides the role from which one is inserted.
Where It Appears
- Phones acting as USB hosts
- Some cameras and camcorders
- Industrial handhelds and instruments
- Legacy OTG devices
The connector appears where a small device had to be a host before USB-C existed.
Sourcing
| The difficulty | The reason |
|---|---|
| Rarely stocked | Low demand |
| Similar to micro-B | Easy to order wrongly |
| Alternatives | OTG adapters where the device allows |
| Verification | Check both sockets |
The practical answer is often an OTG adapter rather than the exact cable, if the device supports it.
Standards and Verification
| The reference | The relevance |
|---|---|
| USB 2.0 On-The-Go | Micro-A and micro-AB definitions |
| Field test | Device recognised as host |
Per-device socket types are not provided in the knowledge base. The connector definitions are standard; confirm both ends before ordering.
Practical Notes
Because the cable is rare, a photograph of both sockets is worth more than a product description. Micro-A and micro-B look almost identical at a glance, and the wrong one arrives as a plug that fits badly or not at all.
Real-World Applications
The industrial handheld
A handheld acting as host to a card reader: a micro-A to micro-B cable sourced from the device maker – the only reliable supply.
The OTG alternative
A phone with a micro-AB socket: an OTG adapter used instead of the rare cable – same function, easier to replace.
The wrong order
A micro-B to micro-B cable ordered by mistake: it fitted neither role. The sockets photographed and the correct part ordered.
Related reading: OTG adapters in practice — blogs/news/usb-otg-adapter
Related reading: Micro USB connectors — blogs/news/micro-usb-guide
Frequently Asked Questions
What is micro-A?
The host-role variant of the micro connector, with an extra pin.
Why is the cable rare?
Very few devices use micro-A as a host.
Can I use an OTG adapter instead?
Where the device supports it, yes – and it is easier to find.
How do I tell them apart?
Micro-A has a different shell shape; check both sockets.
Sourcing cables for a project, a store, or a private-label line? Contact our B2B sales team for specifications, certification evidence, and volume terms – FOB and CIF options available. Request a quote or sample.