Specifications

Remote Control and Receiver-Transceiver Specifications and Requirements

for Windows Media Center in Windows Operating Systems

not compatible with your IR receiver. Even if you program your hardware to respond to all

protocols that Windows Media Center uses today, you will not be able to program it for all

protocols that Windows Media Center might support in the future. This will lead to support calls

when users expect their ―Media Center Compatible‖ remote to work with your ―Media Center

Compatible‖ receiver.

If your device uses a non-IR transport, then it will not work with any Windows Media Center IR

remotes.

Multiple Keypress Bugs

With the increased number of options for building IR receivers, PCs that have multiple IR

receivers are becoming more and more common. Without software to filter multiple keypresses, a

single remote control press might be received by multiple receivers and passed up to the user

interface multiple times.

Legacy devices, emulator devices, and port driver devices all go through a layer of software that

prevents a single remote control key press from going to the user interface more than once.

HID devices don‘t go through this layer. As a result, two HID receivers may receive the same

keypress and send it up to the user interface, resulting in one keypress per receiver.

Localization Problems

HID Usage Tables, which are defined by the USB Consortium, define number presses based on

the layout of the keyboard. For example, if you press the ―1‖ key on your remote control, the HID

usage sent is tied to the key that is one row down and one key in on a typical American 101-key

keyboard. Certain keyboard layouts, such as Hungarian and French, define this key differently.

As such, if you press the ―1‖ key on a remote control connected to a PC on a French or

Hungarian PC, you may not actually get a ―1‖ key press.

If you implement a device that sends HID codes directly, testing on all locales and with all

keyboard layouts is necessary. You may need to limit the locales where you can distribute your

remote control and you may need to produce localized remote controls for locales that have

different keyboard layouts.

Registry Changes Necessary for Triple-Tap Operation (Windows Vista Only),

IME, and Numeric Input for Windows 7 and Later

Most of the time, the Windows Media Center UI treats remote control button presses exactly the

same as keyboard presses. One time when this is not the case is when the user is entering text

into a search box using what Microsoft calls ―Triple Tap‖ functionality. More generically, this can

be thought of as a ―remote control specific IME‖ (Input Method Editor). In this case, the Windows

Media Center UI treats the remote control buttons differently. For instance, if you enter ―2‖ on the

remote, it will produce the number ―2‖. If you enter ―2,2‖, it will produce the letter ―A‖. If you enter

―2,2,2‖, it will produce the letter ―B‖, etc.

In order to support this, Windows Media Center determines when a specific keypress comes from

a remote control by looking up the name of the receiver device in a registry table to see if it

matches the list of names of all remote control devices.

To support this scenario with a HID device, you must provide a setup executable that sets this

registry key. You will need to test input scenarios in the Windows Media Center UI and make

sure they work correctly.

Further details on this feature are available from Microsoft.