On this page, it is clear that the pinout for a Micro USB type B is:

VDD (+5V) D- (Data-) D+ (Data+) ID (ID) GND (Ground)

However, when I opened and stripped apart my Micro USB type B, it looks like this, where I have a DGND. Before I ruin another USB cable, how do I know which one has the ID pin instead of the DGND pin? enter image description here

EDIT: The image was gathered from this link, the 'measurements' may be different but visually the pin layout looks the same (i.e. on the underside of the connector it has 1 pinout rather than 2): https://www.aliexpress.com/item/33060931097.html

Edit 2: I found the connecter on a video, here is the timestamp: https://youtu.be/9h78fjnWuA0?t=24

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    \$\begingroup\$ The USB standard does not provide -5 V, so something is wrong with your measurements \$\endgroup\$
    – Linkyyy
    Commented Dec 18, 2022 at 8:05
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    \$\begingroup\$ Depends on the cable. If it's Type A to Micro B the ID pin will be left floating to put the B end in slave mode, so there's no point in making it connectable. And what you've labelled DGND is the shield connection. \$\endgroup\$
    – Finbarr
    Commented Dec 18, 2022 at 11:00
  • \$\begingroup\$ @Finbarr But I don't even have the pinout for it., i.e. it's not floating - it just doesn't seem to exist. Are there 2 types of type B connectors? \$\endgroup\$
    – Annon
    Commented Dec 18, 2022 at 11:12

1 Answer 1


Firstly, that's a really unhelpfully labelled image. Really it should be:

  • +5V - 5V supply rail (labelled 5V+ on your diagram)
  • D-/D+ - Data lines (correctly labelled on your diagram)
  • GND - Ground for data and power (unhelpfully labelled 5V- on your diagram)
  • Shield - The connector metal shielding (wrongly labelled DGND)

These are the five wires that run in any standard USB2.0 cable. I say wires, the shield is usually a braided shell encasing the other four wires. Sometimes the shield is omitted in poor quality cables.

The ID is a function of the socket and not the cable. On ports which are capable of dual role host and device (such as mobile phones), also known as On-The-Go (OTG) ports, this pin selects whether the port is host (shorted to GND internally by the plug) or a device (floating).

Because the ID is not connected to a wire, it is not surprising that it isn't broken out to a pad for attaching a wire too. Instead it will internally within the plug be directly shorted to the adjacent GND pin, or simply left unconnected to anything (a.k.a floating).

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    \$\begingroup\$ "horribly incorrectly labelled 5V- on your diagram" - well, uncommon but not horribly wrong. "-5V" would be wrong as there is no negative voltage. I read "5V-" as "5V rail, negative wire". Might make more sense if there are several rails floating with respect to each other. \$\endgroup\$
    – asdfex
    Commented Dec 18, 2022 at 12:11
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    \$\begingroup\$ @asdfex It's horrible labelling. 0V or GND make it clear that all the other pins are referenced to this one. 5V+ and 5V- imply that the D+/D- pins are completely isolated from these two, which is not the case. \$\endgroup\$
    – Finbarr
    Commented Dec 18, 2022 at 13:07
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    \$\begingroup\$ @Annon see en.wikipedia.org/wiki/USB_hardware#USB_On-The-Go_connectors and the two Mini and two Micro plugs. Both of them have A and B types. The AB types are designed to indicate which one is host-side (A) and which one is device-side (B). There are also matching host/device sockets. The fun part is that you can put a B-type cable plug into both A and B sockets (so a host-capable device can work both as Host and as Device), but you can't put a A-type cable plug into B-type socket (so a dumb device-only device can't accept a host-side on the cable, such cables are 'directional!). \$\endgroup\$ Commented Dec 18, 2022 at 22:00
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    \$\begingroup\$ @Annon But interestingly, it's only true for Mini and Micro. Because they are newer inventions. The oldest "classic" type-A and type-B (the 'computer one' and the 'printer one' :) ) are not designed to work that way, type-A plug won't fit into type-B socket. They simply didn't consider back then that it's handy to allow for such reuse.. Anyways, totally in theory in a perfect world, you'd just look at the socket and at the cables and bang you know it. \$\endgroup\$ Commented Dec 18, 2022 at 22:07
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    \$\begingroup\$ @Annon But the reality, cheap cables won't follow anything. I'm sure you can even buy B-B cables that should have NO sense (bus needs a host!). Half of my USB cables are "data-only", because the manufacturer cut the cost and included only 2 lines instead of 5 (who needs d+/d-/shield to charge a night lamp, right?). I am 100% you can easily find nice-looking cables that should be OTG-capable with proper A/B ends, that won't follow the standard. I'd say, if you need it badly, instead of destroying the cables open, just grab two HOST side sockets and make a trivial tester. \$\endgroup\$ Commented Dec 18, 2022 at 22:12

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