: How do it know?

2009-10-09, 08:00 PM
Like the old joke about thermos being able to keep colds cold and hots hot: how does it know?

What is the method by which the satellite is able turn on and off an XM or Sirius tuner? If a tuner is not powered up at the right time, will it miss its wake-up call? What actually happens inside the tuner to make it active? Is there a lot of bandwidth expended in this kind of housekeeping-signal going out all the time?

Questions, questions, questions....

2009-10-09, 09:37 PM
Not quite sure what you're asking? A satellite doesn't turn your receiver on or off, your power button does. The satellite simply broadcasts the content on your channels, this goes on whether your particular receiver is on, there is no two way communication as far as I understand it. Maybe I'm not understanding your question?

2009-10-10, 06:00 AM
The satellites broadcast the ID of the enabled receivers at some interval. More correctly the uplink includes the ID numbers of the enabled receivers into the data stream to the satellite transponder which rebroadcasts. The receivers have to receive that enabling signal which ( I don't know) may contain the decryption key for the broadcast every so often to keep working.

The same sort of thing applies to satellite TV signals.

2009-10-10, 07:42 AM
Wgauci, I guess I wasn't as clear as I should have been. I was wondering about the activation and deactivation of a radio (upon payment or nonpayment of a subscription).

Tim, do you know how that actually works? If I am a tuner, what is it that a satelite signal can do to me when it calls my name (as it were) that would make me start producing decrypted sound?

Then, for deactivation, does the satellite have to call my name forever for me to be certainly deactivated? How would the satellite know that I have been listening, and thus deactivated -- so does that data stream have to just grow and grow and grow?

Oh, the puzzles of life....

2009-10-10, 12:59 PM
It sends you a control message with the current authorization keys. If you unsubscribe, it will send null keys or a command to dump the current valid key.

By you, I mean a message to the SID or your tuner. It will send a signal within minutes of your account status changing, and on a carousel of status key updates, in case your tuner is not connected at the time of the change or key update.

As said, it is the same general principal pay TV boxes work on.