Specifications

Remote Control and Receiver-Transceiver Specifications and Requirements
for Windows Media Center in Windows Operating Systems
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 Power consumption requirements are defined by the bus and architecture used by the IR
receiver. For example, USB allows 2.5 mA during suspend and a variable amount of current
depending on whether it is a high-power or lower-power device.
 If using a USB device, it is recommended that the device be able to operate correctly when it is
plugged into a passive hub.
 It must properly indicate user presence to the operating system when waking the system. This
can be tested by first waking the system with the remote control, and then by running a
scheduled task. The monitor should turn on when waking from the remote control, but not when
waking from running a scheduled task
 It needs to fire a hardware interrupt to wake the system when it sees the Sleep key's IR
signature.
 It needs to be software-configurable. Depending on what IR protocol is being used, the IR
signature for the Sleep key can change from computer to computer. This signature is stored in
the registry. The IR port driver needs to take this information from the registry and program the
hardware to wake on this signature.
 It needs to call PoSetSystemState(ES_USER_PRESENT) when the device causes the system to
wake up. This call causes the computer to turn on video and audio. It is important to do this only
when the user presses the Sleep button on the remote. Because this call causes video and audio
to start playing, implementing it incorrectly could cause the computer to turn on and play music in
the middle of the night.
Wake Signatures
A wake signature is an IR pattern that represents a remote control key that can wake the PC from
a low-power state. There are different wake signatures required for device operation:
 RC6 Protocol, Sleep Toggle Key (most common and currently the default signature)
 RC6 Protocol, Discrete Wake
 Quatro Pulse Protocol, Sleep Toggle Key
 Quatro Pulse Protocol, Discrete Wake
Note that there is no wake signature for the Discrete Sleep keys because these keys are
designed to put the PC into a low-power state. They are not designed to wake the PC from a low-
power state, so they are not included in the list of wake patterns.
It is worth noting that the payloads for these patterns have a number of bits that aren‘t significant
for wake functioning. The implementation should be aware of these bits and ignore them
accordingly.
 The RC6 protocol has a toggle bit. The wake pattern decoding should ignore this toggle bit.
 The Quatro Pulse protocol has a checksum bit. The wake pattern decoding should ignore this
checksum bit.
These bits are indicated in the table below.
Note It is important to implement these bits properly—specifically the address bits. Many wake
implementations have failed to implement these properly in the past.
Protocol
Button
Button
Code
Payload
Don’t Care
Bits
RC6
Sleep
12
Customer
Toggle Bit