Question: When did the ITU announce that it had embraced micro-USB as the Universal Charging Solution?
Answer: 22 October 2009

Question: What has energy-efficient one-charger-fits-all new mobile phone solution?
Answer: micro-USB

Question: Who defined a common External Power Supply for use with smartphones sold?
Answer: The European Standardisation Bodies CEN, CENELEC and ETSI

Question: How many mobile phone manufacturers signed the EU's common EPS (MoU)?
Answer: 14

Question: Who was one of the original MoU signers?
Answer: Apple

Question: What are all USB On-The-Go devices required to have?
Answer: one, and only one, USB connector

Question: Non-OTG compliant devices are not allowed to use what?
Answer: the micro-AB receptacle

Question: Why are the Non-OTG compliant devices not allowed to use the micro-AB receptacle?
Answer: power supply shorting hazards on the VBUS line

Question: The OTG device with the B-plug inserted is called what?
Answer: B-device

Question: What does an OTG device default to with no plug inserted?
Answer: to acting as a B-device

Question: What is the A-device responsible for?
Answer: powering the USB interface when required

Question: What is USB?
Answer: a serial bus

Question: What kind of wires does the USB 2.0 variant use?
Answer: four shielded wires

Question: What are the four shielded wires in the USB 2.0 variant used for?
Answer: two for power (VBUS and GND), and two for differential data signals

Question: How long is the maximum cable length the USB 2.0 provides?
Answer: 5 meters for devices running at Hi Speed

Question: What is the maximum acceptable delay per cable?
Answer: 26 ns

Question: What does theUSB 2.0 specification require?
Answer: cable delay be less than 5.2 ns per meter

Question: What is a unit load defined as?
Answer: 100 mA in USB 1.x and 2.0

Question: How much is a unit load in USB 3.0?
Answer: 150 mA

Question: What is the maximum amount of load a USB 1. and 2.0 device may draw?
Answer: five unit loads

Question: What is the maximum amount of load a USB 3.0 device may draw?
Answer: six unit loads

Question: What is an example of a device that requires more than 500 mA of current?
Answer: high-speed external disk drives

Question: What is an issue that may occur if a high-speed external disk drive is powered from just one USB 2.0 port.
Answer: may have power issues

Question: What does USB compliance specification prohibit?
Answer: "use of a 'Y' cable (a cable with two A-plugs)

Question: What defines a new type of USB port, called the charging port?
Answer: The USB Battery Charging Specification Revision 1.1

Question: When was the USB Battery Charging Specification Revision 1.1 released?
Answer: in 2007

Question: What was the USB Battery Charging Specification Revision 1.1 called?
Answer: the charging port

Question: What does a charging port supply?
Answer: up to 500 mA at 5 V

Question: How many types of charging ports exist?
Answer: Two types

Question: What can a portable device recognize?
Answer: the type of USB port

Question: What are the D+ and D- shortened with?
Answer: a resistance not exceeding 200 ohms

Question: What does the USB Battery Charging Specification Revision 1.2 make clear of?
Answer: there are safety limits to the rated current at 5 A coming from USB 2.0

Question: What does revision 1.2 remove?
Answer: USB ports type detection via resistive detection mechanisms

Question: When was USB Battery Charging Specification Revision 1.2 released?
Answer: in 2010

Question: When did the USB Promoters Group announce the finalization of the USB Power Delivery specification?
Answer: In July 2012

Question: What can devices request?
Answer: higher currents and supply voltages from compliant hosts

Question: In all cases, both host-to-device and device-to-host configurations are what?
Answer: supported

Question: The USB Power Delivery revision 2.0 specification has been released as part of what?
Answer: USB 3.1

Question: What does the USB Power Delivery revision 2.0 specification cover?
Answer: Type-C cable and connector with four power/ground pairs and a separate configuration channel

Question: Power delivery protocols have been updated to facilitate what?
Answer: Type-C features

Question: What can sleep-and-charge USB ports be used to do?
Answer: charge electronic devices even when the computer is switched off

Question: What is normally powered off whenever the computer is off?
Answer: USB ports

Question: What remain powered even whenever the computer is powered off?
Answer: Sleep-and-charge USB ports

Question: On what laptops are the USB ports marked with a USB symbol with an added lightening bolt icon?
Answer: On Dell and Toshiba laptops

Question: What does dell call the feature that lets USB drives to remain powered when the computer is off?
Answer: PowerShare

Question: On what laptops are the sleep-and-charge marked with a non-standard symbol?
Answer: On Acer Inc. and Packard Bell laptops

Question: When did the GSM Association follow suit?
Answer: 17 February 2009

Question: UCS chargers will also include what?
Answer: a 4-star or higher efficiency rating

Question: When was this further endorsed by the CTIA?
Answer: 22 April 2009

Question: When did many of the largest mobile phone manufacturers sign an EC-sponsored MoU?
Answer: June 2009

Question: What did the MoU make the manufacturers agree to do?
Answer: to make most data-enabled mobile phones marketed in the European Union compatible with a common External Power Supply

Question: When did the IEC release its version of the common EPS standard as IEC 62684:2011?
Answer: January 2011

Question: Some USB devices require what?
Answer: more power than is permitted by the specifications for a single port.

Question: Some devices such as an external hard and optical disk drive can use what?
Answer: an external power supply

Question: What is another alternative for power for an external hard and optical disk drive?
Answer: a dual-input USB cable

Question: What is the purpose of a dual-input USB cable?
Answer: one input of which is used for power and data transfer, the other solely for power

Question: What does the USB specification limit?
Answer: the inrush current

Question: When is the inrush current affected by the USB specification?
Answer: when the device is first connected

Question: What are USB devices required to enter?
Answer: ultra low-power suspend mode when the USB host is suspended

Question: Many USB host interfaces do not what?
Answer: cut off the power supply to USB devices when they are suspended

Question: What do some non-standard USB devices use?
Answer: the 5 V power supply without participating in a proper USB network

Question: What Negotiates power draw with the host interface?
Answer: the 5 V power supply

Question: What does the USB specification require prior to the Battery Charging Specification?
Answer: that devices connect in a low-power mode (100 mA maximum) and communicate their current requirements to the host

Question: How is the USB data transmitted?
Answer: by toggling the data lines between the J state and the opposite K state

Question: What does USB use to encode data?
Answer: the NRZI line coding

Question: To ensure a minimum density of signal transitions  remains in the bitsream, what does USB use?
Answer: bit stuffing

Question: What is a USB packet's end called?
Answer: EOP (end-of-packet)

Question: What can skew due to hubs add?
Answer: as much as one bit time before the SE0 of the end of packet

Question: What can this extra bit result in?
Answer: "bit stuff violation

Question: What type of protocol is used for USB 2.0 devices during a reset?
Answer: a special protocol

Question: What is the special protocol during a USB 2.0 device reset called?
Answer: chirping

Question:  A device that is HS capable first connects as a what?
Answer: an FS device (D+ pulled high)