|4||ID||Mode Detect. May be N/C, GND or used as an attached device presence indicator (shorted to GND with resistor)|
USB pinout signals
USB is a serial bus. It uses 4 shielded wires: two for power (+5v & GND) and two for differential data signals (labelled as D+ and D- in pinout). NRZI (Non Return to Zero Invert) encoding scheme used to send data with a sync field to synchronise the host and receiver clocks. In USB data cable Data+ and Data- signals are transmitted on a twisted pair. No termination needed. Half-duplex differential signaling helps to combat the effects of electromagnetic noise on longer lines. Contrary to popular belief, D+ and D- operate together; they are not separate simplex connections.
The exact connector name is Micro-USB C or Micro-USB AB connector and it is documented in the USB standards, although some added pseudo-standards are found in the common implementation that are neither disallowed nor explicitly required by the documentation.
The device with the 5-pin connector has a pullup to high on the connector.
Low (small value resistor to ground or connection to ground) if you are connecting an accessory that the device must ask as a host for.
Let it remain high (no-connect) for a connection that the device should remain in normal (slave/client/peripheral) mode for.
Additional Psuedo-standard added by some device manufacturers: If there is no-connect on the data pins, the device will assume it is connected to a charging only cable.
Additionally, most devices can receive power in host mode, even though this is not part of the standard.