romikgosai/squad_modified huggingface dataset:
Full-featured USB Type-C cables are active, electronically marked cables that contain a chip with an ID function based on the configuration data channel and vendor-defined messages (VDMs) from the USB Power Delivery 2.0 specification. USB Type-C devices also support power currents of 1.5 A and 3.0 A over the 5 V power bus in addition to baseline 900 mA; devices can either negotiate increased USB current through the configuration line, or they can support the full Power Delivery specification using both BMC-coded configuration line and legacy BFSK-coded VBUS line.

Questions and answers:
['
Q: Electronically marked cables have a chip that contains what?
A: an ID function based on the configuration data channel and vendor-defined messages', '
Q: What kind of cables does the fully featured USB Type-C contain?
A: active, electronically marked cables', '
Q: What is the shortened version of vendor-defined messages?
A: (VDMs)']
The design architecture of USB is asymmetrical in its topology, consisting of a host, a multitude of downstream USB ports, and multiple peripheral devices connected in a tiered-star topology. Additional USB hubs may be included in the tiers, allowing branching into a tree structure with up to five tier levels. A USB host may implement multiple host controllers and each host controller may provide one or more USB ports. Up to 127 devices, including hub devices if present, may be connected to a single host controller. USB devices are linked in series through hubs. One hub—built into the host controller—is the root hub.

Questions and answers:
['
Q: The design of USB is asymmetrical in what?
A: its topology', '
Q: How many devices may be connected to a host controller?
A: 127 devices', '
Q: How are USB devices linked?
A: in series through hubs', '
Q: What HUB is built into the host controller?
A: the root hub', '
Q: The design of the USB is asymmetrical in its what?
A: topology', '
Q: How many devices can be connected to a host controller?
A: Up to 127 devices', '
Q: What hub is built into the host controller?
A: the root hub', '
Q: A USB host may implement how many host controllers?
A: multiple', '
Q: How many USB ports may a host controller provide?
A: one or more USB ports']
A physical USB device may consist of several logical sub-devices that are referred to as device functions. A single device may provide several functions, for example, a webcam (video device function) with a built-in microphone (audio device function). This kind of device is called a composite device. An alternative to this is compound device, in which the host assigns each logical device a distinctive address and all logical devices connect to a built-in hub that connects to the physical USB cable.

Questions and answers:
['
Q: What are logical sub-devices referred to as?
A: device functions', '
Q: A single device can provide an audio device function such as?
A: built-in microphone', '
Q: A single device can provide a video device function such as?
A: a webcam']
USB device communication is based on pipes (logical channels). A pipe is a connection from the host controller to a logical entity, found on a device, and named an endpoint. Because pipes correspond 1-to-1 to endpoints, the terms are sometimes used interchangeably. A USB device could have up to 32 endpoints (16 IN, 16 OUT), though it's rare to have so many. An endpoint is defined and numbered by the device during initialization (the period after physical connection called "enumeration") and so is relatively permanent, whereas a pipe may be opened and closed.

Questions and answers:
['
Q: What is a pipe?
A: a connection from the host controller to a logical entity', '
Q: A USB connection is based on what?
A: pipes (logical channels)', '
Q: What is a pipe named at?
A: an endpoint', '
Q: Where do pipes correspond?
A: 1-to-1 to endpoints', '
Q: How many endpoints can a USB device have?
A: up to 32 endpoints']
An endpoint of a pipe is addressable with a tuple (device_address, endpoint_number) as specified in a TOKEN packet that the host sends when it wants to start a data transfer session. If the direction of the data transfer is from the host to the endpoint, an OUT packet (a specialization of a TOKEN packet) having the desired device address and endpoint number is sent by the host. If the direction of the data transfer is from the device to the host, the host sends an IN packet instead. If the destination endpoint is a uni-directional endpoint whose manufacturer's designated direction does not match the TOKEN packet (e.g. the manufacturer's designated direction is IN while the TOKEN packet is an OUT packet), the TOKEN packet is ignored. Otherwise, it is accepted and the data transaction can start. A bi-directional endpoint, on the other hand, accepts both IN and OUT packets.

Questions and answers:
['
Q: If the direction of the data transfer is from the device to the host, what does the host send?
A: the host sends an IN packet', '
Q: What does a bi-directional endpoint accept?
A: both IN and OUT packets', '
Q: What is sent if the direction of the data transfer is from host to endpoint?
A: an OUT packet']
When a USB device is first connected to a USB host, the USB device enumeration process is started. The enumeration starts by sending a reset signal to the USB device. The data rate of the USB device is determined during the reset signaling. After reset, the USB device's information is read by the host and the device is assigned a unique 7-bit address. If the device is supported by the host, the device drivers needed for communicating with the device are loaded and the device is set to a configured state. If the USB host is restarted, the enumeration process is repeated for all connected devices.

Questions and answers:
['
Q: What is started when a USB is first connected to a host?
A: enumeration process', '
Q: What id the data rate determined during?
A: the reset signaling', '
Q: When is the device assigned a unique 7-bit address?
A: After reset', '
Q: What does the enumeration process start by doing?
A: sending a reset signal to the USB device', '
Q: What happens whenever a USB host is restarted?
A: the enumeration process is repeated for all connected devices.']
High-speed USB 2.0 hubs contain devices called transaction translators that convert between high-speed USB 2.0 buses and full and low speed buses. When a high-speed USB 2.0 hub is plugged into a high-speed USB host or hub, it operates in high-speed mode. The USB hub then uses either one transaction translator per hub to create a full/low-speed bus routed to all full and low speed devices on the hub, or uses one transaction translator per port to create an isolated full/low-speed bus per port on the hub.

Questions and answers:
['
Q: What do transaction translators do?
A: convert between high-speed USB 2.0 buses and full and low speed buses', '
Q: When does a USB 2.0 hub operate in high speed mode?
A: When a high-speed USB 2.0 hub is plugged into a high-speed USB host or hub', "
Q: What kind of devices do High speed USB 2.0's contain?
A: transaction translators"]
USB implements connections to storage devices using a set of standards called the USB mass storage device class (MSC or UMS). This was at first intended for traditional magnetic and optical drives and has been extended to support flash drives. It has also been extended to support a wide variety of novel devices as many systems can be controlled with the familiar metaphor of file manipulation within directories. The process of making a novel device look like a familiar device is also known as extension. The ability to boot a write-locked SD card with a USB adapter is particularly advantageous for maintaining the integrity and non-corruptible, pristine state of the booting medium.

Questions and answers:
["
Q: What do USB's implement connections to?
A: storage devices", '
Q: What are the standards called that implement connections to storage devices?
A: the USB mass storage device class (MSC or UMS)', '
Q: What is the process of making a novel device look like a familiar device?
A: extension', '
Q: Why is the ability to boot write-locked SD cards with a USB adapter advantageous for?
A: maintaining the integrity and non-corruptible, pristine state of the booting medium.']
Though most computers since mid-2004 can boot from USB mass storage devices, USB is not intended as a primary bus for a computer's internal storage. Buses such as Parallel ATA (PATA or IDE), Serial ATA (SATA), or SCSI fulfill that role in PC class computers. However, USB has one important advantage, in that it is possible to install and remove devices without rebooting the computer (hot-swapping), making it useful for mobile peripherals, including drives of various kinds (given SATA or SCSI devices may or may not support hot-swapping).

Questions and answers:
['
Q: Since when can most computers boot from USB mass storage devices?
A: since mid-2004', "
Q: What is USB not intended for?
A: a primary bus for a computer's internal storage", '
Q: What is an important advantage of USB?
A: it is possible to install and remove devices without rebooting the computer', "
Q: Buses such as Parallel ATA fulfill what role in PC computers?
A: a computer's internal storage"]
Firstly conceived and still used today for optical storage devices (CD-RW drives, DVD drives, etc.), several manufacturers offer external portable USB hard disk drives, or empty enclosures for disk drives. These offer performance comparable to internal drives, limited by the current number and types of attached USB devices, and by the upper limit of the USB interface (in practice about 30 MB/s for USB 2.0 and potentially 400 MB/s or more for USB 3.0). These external drives typically include a "translating device" that bridges between a drive's interface to a USB interface port. Functionally, the drive appears to the user much like an internal drive. Other competing standards for external drive connectivity include eSATA, ExpressCard, FireWire (IEEE 1394), and most recently Thunderbolt.

Questions and answers:
['
Q: Several manufacturers offer what?
A: external portable USB hard disk drives', '
Q: What do external portable USB hard drive disks offer?
A: performance comparable to internal drives', '
Q: What is the most recent standard for external drive connectivity?
A: Thunderbolt', '
Q: What do the external drives typically include?
A: a "translating device"']
Media Transfer Protocol (MTP) was designed by Microsoft to give higher-level access to a device's filesystem than USB mass storage, at the level of files rather than disk blocks. It also has optional DRM features. MTP was designed for use with portable media players, but it has since been adopted as the primary storage access protocol of the Android operating system from the version 4.1 Jelly Bean as well as Windows Phone 8 (Windows Phone 7 devices had used the Zune protocol which was an evolution of MTP). The primary reason for this is that MTP does not require exclusive access to the storage device the way UMS does, alleviating potential problems should an Android program request the storage while it is attached to a computer. The main drawback is that MTP is not as well supported outside of Windows operating systems.

Questions and answers:
['
Q: Media Transfer Protocol was designed by who?
A: Microsoft', "
Q: Why was Media Transfer Protocol designed?
A: to give higher-level access to a device's filesystem", '
Q: What was MTP originally designed for?
A: use with portable media players', '
Q: Why has MTP become the primary storage access protocol of the Android operating system?
A: MTP does not require exclusive access to the storage device the way UMS does']
USB mice and keyboards can usually be used with older computers that have PS/2 connectors with the aid of a small USB-to-PS/2 adapter. For mice and keyboards with dual-protocol support, an adaptor that contains no logic circuitry may be used: the hardware in the USB keyboard or mouse is designed to detect whether it is connected to a USB or PS/2 port, and communicate using the appropriate protocol. Converters also exist that connect PS/2 keyboards and mice (usually one of each) to a USB port. These devices present two HID endpoints to the system and use a microcontroller to perform bidirectional data translation between the two standards.

Questions and answers:
['
Q: What do older computers have to have in order for USB mice and keyboards to be used?
A: PS/2 connectors with the aid of a small USB-to-PS/2 adapter', '
Q: What is the hardware designed to detect in USB mice and keyboards?
A: whether it is connected to a USB or PS/2 port', '
Q: USB keyboards and mice may communicate using what?
A: appropriate protocol', '
Q: What connects PS/2 keyboards and mice to a USB port?
A: Converters', '
Q: What performs bidirectional data translation between two standards?
A: a microcontroller']
By design, it is difficult to insert a USB plug into its receptacle incorrectly. The USB specification states that the required USB icon must be embossed on the "topside" of the USB plug, which "...provides easy user recognition and facilitates alignment during the mating process." The specification also shows that the "recommended" "Manufacturer's logo" ("engraved" on the diagram but not specified in the text) is on the opposite side of the USB icon. The specification further states, "The USB Icon is also located adjacent to each receptacle. Receptacles should be oriented to allow the icon on the plug to be visible during the mating process." However, the specification does not consider the height of the device compared to the eye level height of the user, so the side of the cable that is "visible" when mated to a computer on a desk can depend on whether the user is standing or kneeling.

Questions and answers:
['
Q: What is difficult to do with a USB plug?
A: to insert a USB plug into its receptacle incorrectly', '
Q: The USB specification states that the required USB icon must be what?
A: embossed on the "topside" of the USB plug', '
Q: How is the USB icon located to each receptacle?
A: adjacent', '
Q: Receptacles should be oriented to allow the icon on the plug to what?
A: to be visible during the mating process']
The standard connectors were deliberately intended to enforce the directed topology of a USB network: Type-A receptacles on host devices that supply power and Type-B receptacles on target devices that draw power. This prevents users from accidentally connecting two USB power supplies to each other, which could lead to short circuits and dangerously high currents, circuit failures, or even fire. USB does not support cyclic networks and the standard connectors from incompatible USB devices are themselves incompatible.

Questions and answers:
['
Q: What do Type-A receptacles do on host devices?
A: supply power', '
Q: What do Type-b receptacles do on target devices?
A: draw power', '
Q: What do the receptacles prevent user from doing?
A: from accidentally connecting two USB power supplies to each other', '
Q: What networks do USB not support?
A: cyclic networks']
The standard connectors were designed to be robust. Because USB is hot-pluggable, the connectors would be used more frequently, and perhaps with less care, than other connectors. Many previous connector designs were fragile, specifying embedded component pins or other delicate parts that were vulnerable to bending or breaking. The electrical contacts in a USB connector are protected by an adjacent plastic tongue, and the entire connecting assembly is usually protected by an enclosing metal sheath.

Questions and answers:
['
Q: Standard connectors were designed to be what?
A: robust', '
Q: Why were standard connectors designed to be so robust?
A: the connectors would be used more frequently', '
Q: What as a drawback of previous connectors?
A: Many previous connector designs were fragile', '
Q: How are the electrical contents of a USB connector protected?
A: by an adjacent plastic tongue', '
Q: How is the entire connecting assembly of a USB connector protected?
A: by an enclosing metal sheath']
The connector construction always ensures that the external sheath on the plug makes contact with its counterpart in the receptacle before any of the four connectors within make electrical contact. The external metallic sheath is typically connected to system ground, thus dissipating damaging static charges. This enclosure design also provides a degree of protection from electromagnetic interference to the USB signal while it travels through the mated connector pair (the only location when the otherwise twisted data pair travels in parallel). In addition, because of the required sizes of the power and common connections, they are made after the system ground but before the data connections. This type of staged make-break timing allows for electrically safe hot-swapping.

Questions and answers:
['
Q: Where is the external metallic sheet connected?
A: typically connected to system ground', '
Q: What provides a degree of protection from interference with the USB signal?
A: This enclosure design', '
Q: This type of stage make-break timing allows for what?
A: electrically safe hot-swapping.']
The newer micro-USB receptacles are designed for a minimum rated lifetime of 10,000 cycles of insertion and removal between the receptacle and plug, compared to 1,500 for the standard USB and 5,000 for the mini-USB receptacle. Features intended to accomplish include, a locking device was added and the leaf-spring was moved from the jack to the plug, so that the most-stressed part is on the cable side of the connection. This change was made so that the connector on the less expensive cable would bear the most wear instead of the more expensive micro-USB device. However the idea that these changes did in fact make the connector more durable in real world use has been widely disputed, with many contending that they are in fact, much less durable.

Questions and answers:
['
Q: What are the newer micro-USB receptacles designed for?
A: a minimum rated lifetime of 10,000 cycles of insertion', '
Q: What is the minimum rated lifetime for the standard USB receptacle?
A: 1,500', '
Q: After a leaf-spring was moved from jack to the plug, the most stressed part was found where?
A: on the cable side of the connection', '
Q: Why was the change made for the USB device?
A: so that the connector on the less expensive cable would bear the most wear']
The USB standard specifies relatively loose tolerances for compliant USB connectors to minimize physical incompatibilities in connectors from different vendors. To address a weakness present in some other connector standards, the USB specification also defines limits to the size of a connecting device in the area around its plug. This was done to prevent a device from blocking adjacent ports due to the size of the cable strain relief mechanism (usually molding integral with the cable outer insulation) at the connector. Compliant devices must either fit within the size restrictions or support a compliant extension cable that does.

Questions and answers:
['
Q: What type of tolerances does the USB standard specify for compliant USB connectors?
A: loose tolerances', '
Q: Why were loose tolerances allowed for compliant USB connectors?
A: to minimize physical incompatibilities in connectors from different vendors', '
Q: How is a weakness addressed in some other connector standards?
A: the USB specification also defines limits to the size of a connecting device', '
Q: Due to size restrictions compliant devices must what?
A: fit within the size restrictions or support a compliant extension cable that does']
In general, USB cables have only plugs on their ends, while hosts and devices have only receptacles. Hosts almost universally have Type-A receptacles, while devices have one or another Type-B variety. Type-A plugs mate only with Type-A receptacles, and the same applies to their Type-B counterparts; they are deliberately physically incompatible. However, an extension to the USB standard specification called USB On-The-Go (OTG) allows a single port to act as either a host or a device, which is selectable by the end of the cable that plugs into the receptacle on the OTG-enabled unit. Even after the cable is hooked up and the units are communicating, the two units may "swap" ends under program control. This capability is meant for units such as PDAs in which the USB link might connect to a PC's host port as a device in one instance, yet connect as a host itself to a keyboard and mouse device in another instance.

Questions and answers:
['
Q: USB cables and device have only what on their ends?
A: plugs', '
Q: Hosts and devices only have what in terms of connecting to a USB device?
A: receptacles', '
Q: Devices usually have what type of receptacle?
A: one or another Type-B variety', '
Q: Hosts almost always have what type of receptacle?
A: Type-A receptacles']
Various connectors have been used for smaller devices such as digital cameras, smartphones, and tablet computers. These include the now-deprecated (i.e. de-certified but standardized) mini-A and mini-AB connectors; mini-B connectors are still supported, but are not OTG-compliant (On The Go, used in mobile devices). The mini-B USB connector was standard for transferring data to and from the early smartphones and PDAs. Both mini-A and mini-B plugs are approximately 3 by 7 mm; the mini-A connector and the mini-AB receptacle connector were deprecated on 23 May 2007.

Questions and answers:
['
Q: What has been used to connect digital cameras. smartphones and other devices to tablet computers?
A: Various connectors', '
Q: What was standard for transferring data to and from the earlier type of smartphones?
A: The mini-B USB connector', '
Q: How large are both mini-A and mini-B plugs?
A: approximately 3 by 7 mm', '
Q: When were the mini-A connector and and the mini-AB receptacle connector depreceated?
A: 23 May 2007']
The micro plug design is rated for at least 10,000 connect-disconnect cycles, which is more than the mini plug design. The micro connector is also designed to reduce the mechanical wear on the device; instead the easier-to-replace cable is designed to bear the mechanical wear of connection and disconnection. The Universal Serial Bus Micro-USB Cables and Connectors Specification details the mechanical characteristics of micro-A plugs, micro-AB receptacles (which accept both micro-A and micro-B plugs), and micro-B plugs and receptacles, along with a standard-A receptacle to micro-A plug adapter.

Questions and answers:
['
Q: What is the micro connector designed for?
A: to reduce the mechanical wear on the device', '
Q: What is the easier-to-replace cable designed for?
A: to bear the mechanical wear of connection and disconnection', '
Q: What is the micro-plug rated for?
A: 10,000 connect-disconnect cycles']
The cellular phone carrier group Open Mobile Terminal Platform (OMTP) in 2007 endorsed micro-USB as the standard connector for data and power on mobile devices In addition, on 22 October 2009 the International Telecommunication Union (ITU) has also announced that it had embraced micro-USB as the Universal Charging Solution its "energy-efficient one-charger-fits-all new mobile phone solution," and added: "Based on the Micro-USB interface, UCS chargers also include a 4-star or higher efficiency rating—​​up to three times more energy-efficient than an unrated charger."

Questions and answers:
['
Q: In 2007 who endorsed micro-USB as the standard connector for data and power on mobile devices?
A: The cellular phone carrier group Open Mobile Terminal Platform', '
Q: When did the ITU announce that it had embraced micro-USB as the Universal Charging Solution?
A: 22 October 2009', '
Q: What has energy-efficient one-charger-fits-all new mobile phone solution?
A: micro-USB']