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-Version 2009-08-22
-
-==========================
-WHY DO WE NEED THESE IDs?
-==========================
-
-USB is more than a low level protocol for data transport. It also defines a
-common set of requests which must be understood by all devices. And as part
-of these common requests, the specification defines data structures, the
-USB Descriptors, which are used to describe the properties of the device.
-
-From the perspective of an operating system, it is therefore possible to find
-out basic properties of a device (such as e.g. the manufacturer and the name
-of the device) without a device-specific driver. This is essential because
-the operating system can choose a driver to load based on this information
-(Plug-And-Play).
-
-Among the most important properties in the Device Descriptor are the USB
-Vendor- and Product-ID. Both are 16 bit integers. The most simple form of
-driver matching is based on these IDs. The driver announces the Vendor- and
-Product-IDs of the devices it can handle and the operating system loads the
-appropriate driver when the device is connected.
-
-It is obvious that this technique only works if the pair Vendor- plus
-Product-ID is unique: Only devices which require the same driver can have the
-same pair of IDs.
-
-
-=====================================================
-HOW DOES THE USB STANDARD ENSURE THAT IDs ARE UNIQUE?
-=====================================================
-
-Since it is so important that USB IDs are unique, the USB Implementers Forum,
-Inc. (usb.org) needs a way to enforce this legally. It is not forbidden by
-law to build a device and assign it any random numbers as IDs. Usb.org
-therefore needs an agreement to regulate the use of USB IDs. The agreement
-binds only parties who agreed to it, of course. Everybody else is free to use
-any numbers for their IDs.
-
-So how can usb.org ensure that every manufacturer of USB devices enters into
-an agreement with them? They do it via trademark licensing. Usb.org has
-registered the trademark "USB", all associated logos and related terms. If
-you want to put an USB logo on your product or claim that it is USB
-compliant, you must license these trademarks from usb.org. And this is where
-you enter into an agreement. See the "USB-IF Trademark License Agreement and
-Usage Guidelines for the USB-IF Logo" at
-http://www.usb.org/developers/logo_license/.
-
-Licensing the USB trademarks requires that you buy a USB Vendor-ID from
-usb.org (one-time fee of ca. 2,000 USD), that you become a member of usb.org
-(yearly fee of ca. 4,000 USD) and that you meet all the technical
-specifications from the USB spec.
-
-This means that most hobbyists and small companies will never be able to
-become USB compliant, just because membership is so expensive. And you can't
-be compliant with a driver based on V-USB anyway, because the AVR's port pins
-don't meet the electrical specifications for USB. So, in principle, all
-hobbyists and small companies are free to choose any random numbers for their
-IDs. They have nothing to lose...
-
-There is one exception worth noting, though: If you use a sub-component which
-implements USB, the vendor of the sub-components may guarantee USB
-compliance. This might apply to some or all of FTDI's solutions.
-
-
-=======================================================================
-WHY SHOULD YOU OBTAIN USB IDs EVEN IF YOU DON'T LICENSE USB TRADEMARKS?
-=======================================================================
-
-You have learned in the previous section that you are free to choose any
-numbers for your IDs anyway. So why not do exactly this? There is still the
-technical issue. If you choose IDs which are already in use by somebody else,
-operating systems will load the wrong drivers and your device won't work.
-Even if you choose IDs which are not currently in use, they may be in use in
-the next version of the operating system or even after an automatic update.
-
-So what you need is a pair of Vendor- and Product-IDs for which you have the
-guarantee that no USB compliant product uses them. This implies that no
-operating system will ever ship with drivers responsible for these IDs.
-
-
-==============================================
-HOW DOES OBJECTIVE DEVELOPMENT HANDLE USB IDs?
-==============================================
-
-Objective Development gives away pairs of USB-IDs with their V-USB licenses.
-In order to ensure that these IDs are unique, Objective Development has an
-agreement with the company/person who has bought the USB Vendor-ID from
-usb.org. This agreement ensures that a range of USB Product-IDs is reserved
-for assignment by Objective Development and that the owner of the Vendor-ID
-won't give it to anybody else.
-
-This means that you have to trust three parties to ensure uniqueness of
-your IDs:
-
- - Objective Development, that they don't give the same PID to more than
- one person.
- - The owner of the Vendor-ID that they don't assign PIDs from the range
- assigned to Objective Development to anybody else.
- - Usb.org that they don't assign the same Vendor-ID a second time.
-
-
-==================================
-WHO IS THE OWNER OF THE VENDOR-ID?
-==================================
-
-Objective Development has obtained ranges of USB Product-IDs under two
-Vendor-IDs: Under Vendor-ID 5824 from Wouter van Ooijen (Van Ooijen
-Technische Informatica, www.voti.nl) and under Vendor-ID 8352 from Jason
-Kotzin (Clay Logic, www.claylogic.com). Both VID owners have received their
-Vendor-ID directly from usb.org.
-
-
-=========================================================================
-CAN I USE USB-IDs FROM OBJECTIVE DEVELOPMENT WITH OTHER DRIVERS/HARDWARE?
-=========================================================================
-
-The short answer is: Yes. All you get is a guarantee that the IDs are never
-assigned to anybody else. What more do you need?
-
-
-============================
-WHAT ABOUT SHARED ID PAIRS?
-============================
-
-Objective Development has reserved some PID/VID pairs for shared use. You
-have no guarantee of uniqueness for them, except that no USB compliant device
-uses them. In order to avoid technical problems, we must ensure that all
-devices with the same pair of IDs use the same driver on kernel level. For
-details, see the file USB-IDs-for-free.txt.
-
-
-======================================================
-I HAVE HEARD THAT SUB-LICENSING OF USB-IDs IS ILLEGAL?
-======================================================
-
-A 16 bit integer number cannot be protected by copyright laws. It is not
-sufficiently complex. And since none of the parties involved entered into the
-USB-IF Trademark License Agreement, we are not bound by this agreement. So
-there is no reason why it should be illegal to sub-license USB-IDs.
-
-
-=============================================
-WHO IS LIABLE IF THERE ARE INCOMPATIBILITIES?
-=============================================
-
-Objective Development disclaims all liabilities which might arise from the
-assignment of IDs. If you guarantee product features to your customers
-without proper disclaimer, YOU are liable for that.