SuperSpeed OTG devices (SS-OTG) are required to support RSP. Role Swap Protocol (RSP): RSP achieves the same purpose as HNP (i.e., role swapping) by extending standard mechanisms provided by the USB 3.0 specification. By 1987, Ethernet was clearly winning the standards battle over Token Ring, and in the middle of that year, Apple introduced EtherTalk 1.0, an implementation of the AppleTalk protocol over the Ethernet physical layer. The latest version of the supplement also introduced HNP polling, in which the host device periodically polls the peripheral during an active session to determine whether it wishes to become a host. When that camera knows how to talk to the printer, the printer will use HNP to switch to the device role, with the camera becoming the host so pictures stored on the camera can be printed out without reconnecting the cables. Host Negotiation Protocol (HNP): Allows the two devices to exchange their host/peripheral roles, provided both are OTG dual-role devices. Because every OTG controller supports both roles, they are often called "Dual-Role" controllers rather than "OTG controllers". USB OTG recognizes that a device can perform both Host and Peripheral roles, and so subtly changes the terminology.
Standard USB uses a host/device architecture; a host acts as the Host device for the entire bus, and a USB device acts as a Peripheral. When a device is plugged into the USB bus, the host device sets up communications with the device and handles service provisioning (the host's software enables or does the needed data-handling such as file managing or other desired kind of data communication or function). Attach Detection Protocol (ADP): Allows an OTG device, embedded host or USB device to determine attachment status in the absence of power on the USB bus, enabling both insertion-based behavior and the capability to display attachment status. The latest version of the supplement also defines behavior for an Embedded Host which has targeted abilities and the same USB Standard-A port used by PCs. It can accept either a mini-A plug or a mini-B plug, while mini-A adapters allows connection to standard-A USB cables coming from peripherals.
Micro-A adapters allow for connection to standard-A plugs, as used on fixed or standard devices. That allows the devices to be greatly simplified compared to the host; for example, a mouse contains very little logic and relies on the host to do almost all of the work. He would work on the system through 1895 in his lab and then in field tests making improvements to extend its range. These permit the device to work with USB Accessory Charger Adapters that allows the OTG device to be attached to both a charger and another device simultaneously. A charger and either no device or an A-device that is not asserting VBUS (not providing power) are attached. USB OTG introduces the concept of a device performing both Host and Peripheral roles - whenever two USB devices are connected and one of them is a USB OTG device, they establish a communication link.
A multi-media network has to support a broad range of bit-rates demanded by connections, not only because there are many communication media, but also because a communication medium may be encoded by algorithms with different bit-rates. Initially marketed as AppleTalk Personal Network, it comprised a family of network protocols and a physical layer. The new OTG protocols cannot pass through a standard USB hub since they are based on electrical signaling via a dedicated wire. For example, the packaging on a seven-port hub might claim to support a maximum of four full-load devices. If implementing standard USB, devices must assume one role or the other, with computers generally set up as hosts, while (for example) printers normally function as a Peripheral. Also, most gadgets must be either a host or a device. An OTG product must have a single micro-AB receptacle and no other USB receptacles. After initial startup, setup for the bus operates as it does with the normal USB standard, with the A-device setting up the B-device and managing all communications. In the default link configuration, the A-device acts as a USB host with the B-device acting as a USB peripheral. The device connected to the "A" end of the cable at start-up, known as the "A-device", acts as the default host, while the "B" end acts as the default peripheral, known as the "B-device".
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