USB Connectors:
USB connectors come in two flavors: host and peripheral. USB-A Connectors is the standard “host” connector type. USB-B Connectors is a standard for peripheral devices.Polarization: a USB connector can only nominally be inserted one way.
Four Contacts: all USB 2.0 connectors have at least four contacts (USB 3.0 connectors have 9). These are for power (+5 V), ground, and two data lines (D+ and D-).
Electrical Specifications: USB connectors are designed to transmit 5V DC, up to 0.5A for 5 meters.
Protocol: this is a serial bus designed by Compaq, DEC, IBM, Intel, Microsoft, NEC and Nortel in January 1996.
Data Packet: Width=1 bit. Bitrate=1.5-10'000 Mbit/s
