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Overview

What is PoweredUSB?

PoweredUSB provides a single cable connection that supplies both the standard USB communication signals and two additional wire pairs for extra power. The design of PoweredUSB and it’s connectors allow for hot-plugging. This combined with Plug-and-Play operating systems allows PoweredUSB to be easily maintained and supported in the retail environment.

One of the limitations of standard USB is the amount of +5V current available to supply attached peripherals. Normally, 500mA is available at each host port and each powered external hub port. This amount of current is sufficient for most PC type peripherals like mice and keyboards. When the power requirements exceed the 500mA limitation, external peripherals require the use of an external power supply (brick) to supply the necessary power requirements. This limitation takes away from the true "Plug-and-Play" idea conceived for USB peripherals.

The original design of PoweredUSB implementation was a joint effort between IBM and FCI/Berg specifically for IBM retail point-of-sale terminal. While the original understanding is that the connectors and its implementation was going to be unencumbered, IBM was issued a patent on the connection scheme. Read more about IBM's patent.


PoweredUSB components consist of the following:

1. Host-side PCB connector
2. Host-side cable-end plug
3. PoweredUSB cable
4. Peripheral-side cable-end plug
5. Peripheral-side PCB connector

1. Host-side PCB Connector


The host connector incorporates an "A" type socket that allows compatibility of standard USB peripherals. The connector itself is unique in that it provides the additional benefit of a locking mechanism for the cable connector. The host connector's four power pins (two ground and two voltage) are keyed to a specific voltage available at that port..
The following voltage keying options are available:

  • +5V DC at a maximum rating of 6 amps per connector
  • +12V DC at a maximum rating of 6 amps per connector
  • +24V DC at a maximum rating of 6 amps per connector

2. Host-side Cable-end Plug


The cable end is also keyed to match the voltage type and is color coded to simplify voltage identification.

  • +5V (ivory)
  • +12V (teal)
  • +24V (red)

3. PoweredUSB Cable, Bulk

The selection of the raw PoweredUSB cable is critical. This cable is special because not only does it need to transmit data at a high rate but it needs to be able to supply up to 6 amps to meet the PoweredUSB specification. Maximum length recommendation is 4 meters.

There are several manufactures of PoweredUSB cables that are USB 1.1 compliant but only one supplied by CyberData Corporation has been found to be USB 2.0 compliant. Just because a cable constructed seems to function, it may have data loss that is not perceived by the user. It is recommended that purchasers of PoweredUSB cables ask the supplier to confirm USB 1.1 or 2.0 compliance not just a functional test.

4. Peripheral-side Cable-end Plug


The peripheral side connection is loosely defined and generally left to the specific user's physical space requirements. The Series "B" connector as supplied by FCI/Berg is the recommended connector but not mandatory.

The PoweredUSB specification says: "Peripheral side connectors are at the discretion of the manufacture as long as they meet good engineering practices and as long as this connector is not a Host type."


5. Peripheral-side PCB Connector


The peripheral side PCB like the peripheral side cable end, is loosely defined and generally left to the specific user's physical space requirements. The Series “B” connector as supplied by FCI/Berg is the recommended mating connector but not mandatory. The PoweredUSB specification says: “Peripheral side connectors are at the discretion of the manufacturer as long as they meet good engineering practices and as long as this connector is not a host type. 


Hot-Plugging/Hot-Unplugging Considerations

The PoweredUSB connector is not rated to withstand any specific number of arcs which may occur during hot-plugging or hot-unplugging. Since equipment users will associate USB with hot-plugging and hot-unplugging, it is recommended that devices be designed to avoid connector degradation or electronic component failure that could occur if contact arcing is not suppressed. PoweredUSB ground pins make contact before V+. This feature allows for suppression of contact arcing to be designed into the connector.

Peripheral-side connectors that do not incorporate ground first mating may damage the connector or PoweredUSB device by electrical arcing during insertion. (As of April 2006, only Conquest Technology provides a Series "B" staggered pin 1x8 peripheral side PCB connector. PoweredUSB.org has been informed that a Series "B"  2x4 peripheral side PCB connector will be released shortly that also supports hot-plugging with staggered pins.)

Electrical Specifications
For complete electrical specifications, please review the PoweredUSB specification.



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