Specifications

Remote Control and Receiver-Transceiver Specifications and Requirements

for Windows Media Center in Windows Operating Systems

Bluetooth

To build a Bluetooth remote, you would basically be building a Bluetooth keyboard in a remote

control form factor. This device needs to produces the proper HID codes and will have the same

limitations outlined in the section ―HID Device Limitations‖ below.

Things to Remember When Building Your Device

Note the following before you finalize your decision.

Wake from Remote

Wake from remote is the required feature that allows the user to put their PC to sleep using the

Sleep button on their remote and then wake it up again using the Sleep button on their remote.

This will have several effects on your hardware design:

 It implies that your hardware can draw current when the PC is asleep or off. This is necessary

because your hardware needs to watch for and act on the Sleep button.

 It is the one case where your hardware needs to decode the two Media Center IR protocols in

order to wake the system (as described in this document).

 It should ideally be field-programmable so that a given manufacturer could have their PC wake

with the Sleep button on one protocol, and another manufacturer could have their PC wake with

the Sleep button on another protocol

If you use a legacy device, this work is included in the Microsoft-provided design.

Emitter Detection

If you support IR blasting, you need to support an ―Emitter Detection‖ feature. This means that

your hardware/driver must be able to detect the presence of an IR emitter plugged into an emitter

jack.

If you use a legacy device, this work is included in the Microsoft-provided design.

Two Receivers – Long Range and Wide Band

If your hardware supports IR emitting, it needs two IR receivers: a long-range receiver and a

wide-band receiver. The long-range receiver demodulates in hardware, is centered on a

particular frequency, and is designed to work ten meters away from the remote. The wide-band

receiver doesn‘t demodulate in hardware, may not be centered on a particular frequency, and is

designed to work five centimeters away from the remote.

If you use a legacy device, this work is included in the Microsoft-provided design.

Carrier Counting

When using the wide-band receiver, your hardware and/or port driver must be able to return the

carrier frequency of the IR signal to the class driver. This does not need to be an instantaneous

measurement – it merely says ―for the last sample, the carrier frequency was about X KHz‖. This

can most easily be done by counting the number of leading edges in a given signal and dividing

the time that the demodulated signal is high by the number of leading edges.