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Turn On PC remotely?

Discussion in 'Electronic Basics' started by [email protected], Nov 21, 2005.

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  1. Guest

    Anyone know how to turn on a PC from a remote location via a phone
    line, or other method?

    When the power goes out, the PC shuts down, but when power is restored,
    of course the ATX PS won't come on until someone presses the start
    button. Seems to me there would be hardware/some way to trigger that
    power on sequence remotely.

    Without spending hundreds for hardware, anyone have any good ideas of
    how to proceed?


  2. Bob Monsen

    Bob Monsen Guest

    Many modern PCs will restart themselves after a power outage. Also, it is
    possible with many modems to start up the PC when the phone rings. Check
    your BIOS settings.

    Bob Monsen

    Intuition is the undoubting conception of a pure and attentive mind, which
    arises from the light of reason alone, and is more certain than deduction.
    - Descartes
  3. Guest

    Thanks Bob. If you have time, would you elaborate on these 'features?'
    I told my boss the only way to turn on a ATX machine is to do it on the
    "DC" side of the supply, with the cables to the motherboard. Is the
    "auto turn on" a setting in the bios or something? Half the PCs around
    here don't even have switches on the PS, only the one on the tower,
    connected to the MB.

    I am not at all familiar with an ATX machine that will come on when
    power is restored, but then I don't get to see all the PCs that are out
    there, so I am sure you see things that I am uninformed about.

    Do things like the internal modem get power from the supply, even tho
    the motherboard has not turned it on? I guess that might be the key, if
    I can find a way to confirm that the modem would be in a sleep mode. I
    don't have a lot of PCs to look at, let alone up to date machines, so
    anything you can toss out there would be a big help.

    Thanks a lot,

  4. mike

    mike Guest

    wrote in
    ATX supplies and more recent pc motherboards (last 10 years or so) allow
    a number of power on options. Firstly unlike an AT machine ATX pc's are
    always on if there's power on the mains side of the power supply. Even
    when they are turned 'off' by the front switch the pc still has power to
    the MB. Bios settings usually allows a 'wake on' function where if a
    specific keyboard sequence or mouse key is hit the pc will power up.
    Similarly integrated peripherals like lan/nic card or modem often allow a
    wake up on a wake up packet to the lan card or a dial in to the modem.
    seperate lan cards and modem cards often have that feature too. Do a
    google on 'wake on lan' as an example.

    Bios will usually also allow you to set an option in case of power loss.
    Ie, power back up or not. Some Bios will also allow you to set a boot up
    time too.

    Haven't done it but there are some software utilities to do the same,
    that is specifiy a start up time and the pc will boot. I think Windows
    has something similar at some point / version/patch etc but again I've
    never used it.
  5. Guest

    I am not at all familiar with an ATX machine that will come on when
    Three possibilties;

    1. Check the BIOS setup for some power setting option that causes the
    motherboard to control the ATX PS in such a way that it behaves like an
    AT PS of old. If it's there you should be able to figure it out and
    test it.

    2. Wake on Ring (WOR). Allows the computer to power on from off or wake
    from standby/hibernate via a MODEM when the phone rings. Very popular
    for FAX use. Search Google.

    3. Wake On LAN (WOL). As above but using NIC and "magic packet" instead
    of MODEM. Search Google on >WOL subnet<.
  6. Guest

    Check the BIOS setup for some power setting option that causes the
    This BIOS power menu option is called "Restore on AC power loss" on
    ASUS motherboards. If set to "Power On" then the computer will "power
    on" after AC power loss is restored. Look for something similar in your
    motherboard's BIOS.
  7. John G

    John G Guest

    In some machines I use the power option AUTO POWER ON ( in BIOS) is set
    to Everyday 7 AM, then it comes on when I turn the mains power on and
    stays on until the power goes off and comes on again if there is a power
    switchoff and on.
    Seems just what you are asking for.

    One of these machines is in an locked cupboard and is used to control
    all the functions of a 1925 Wurlitzer Theatre organ without any operator
    intervention at the computer keyboard.
  8. Guest

    Many thanks to everyone for the input. I appreciate the help very much.

    I don't wish to appear to not believe folks, so please don't
    misconstrue :) as I went digging even further into the ATX PS specs,
    and so those who have machines that are working are encouraged to tell
    me I read it wrong <g>

    It seems that most, maybe not all, but most of the WOL stuff only work
    if the PC was shutdown from Windows, not from having its power pulled
    from the wall. Near as I can tell, when windows shuts down the PS, if
    it is properly configured to wake up, then it tells the PS, which keeps
    a single power pin on the MB alive for the properly configured NIC to
    stay awake, waiting for the proper packet to arrive and tell it to wake
    up the PS. Basically, under these conditions, the PC is off, but the
    power supply is still on. Can it get into this condition if the input
    to the supply is cycled off and on, as in a power failure?

    I think that as I read ATX v2.01 that a pin is now always live, so that
    a NIC or a modem can be accessed no matter how the PC was shut off, but
    I am not sure I have interpreted that spec correctly. We also don't
    have any ATX 2.01 PS's for me to test with, so I am hoping someone may
    offer a clue.

    Now, I did not ask the question to get folks to answer so I could argue
    :) I just asked, and then spent the day digging through the docs and
    now am a bit confused and want to learn how this works.

    Those who use the wake up feature, does it work if you pull the plug,
    and simulate a power loss, or only when you properly shut down windows?
    I am inclined to think the latter is the only thing that works, in that
    if the power supply is cut off, the BIOS really has nothing more to say
    until the PC boots again.

    Can't say it enough, and will repeat it out of paranoia <g> I didn't
    bring it up to argue it, I am just not able to try a dozen computers
    to see how each one really works, so I am throwing out what I know, to
    compare to those who are wiser, and may well be using this feature
    successfully. Several folks said that they are, but does that include a
    power loss at the input to a supply, as well as a windows shutdown?

    Thanks a lot for the help,

  9. w_tom

    w_tom Guest

    Many know of the ability, but don't really understand how it
    is accomplished. You will find no such ability in the ATX
    power supply specification because the function does not exist
    inside a power supply.

    Power supply is only one part of a power supply 'system'.
    The power supply provides a dedicated voltage (+5VSB) to a
    power supply controller located on motherboard. The power
    supply controller determines how, when, and if power supply
    will turn on. The BIOS has options to change how that power
    supply controller operates. IOW options to power up a supply
    by external events is defined by the power supply controller -
    unique to that motherboard design and setup in CMOS setting -
    what some call the BIOS.

    This power supply controller function is not a Windows
    function even though a Windows program might change a CMOS
  10. Bob Monsen

    Bob Monsen Guest

    Just to add a bit, the ATX power supply has a +5V output that is always
    on, regardless of whether the #PS_ON pin is low or not. This is called the
    +5 VSB output. It is usually limited to 1A or less. It is pin 9 on a
    standard 20 pin molex power connector. It is used to power systems that
    can wake the computer, like Wake On LAN, softmodem, intrusion detection
    systems, and that sort of thing.

    In addition, bios usually have settings for restart after power loss.
    This is critical for server systems, and doesn't depend on the OS, so it
    is probably on your systems unless they are more than 5 years old. Just
    boot into the bios (usually by holding delete, F1, or something like that)
    and look around.

    Bob Monsen

    A great truth is a truth whose opposite is also a great truth.
    - Niels Bohr
  11. Jasen Betts

    Jasen Betts Guest

    Use a modem, and configure the PC for "wake on ring"
    There should be a bios option to make it wake on power being restored.
    Or you could short the green wire on the power connector to one of the black
    wires, that should work too

  12. Guest

    Those who use the wake up feature, does it work if you pull the plug,
    Depends on which Windows you're using, the motherboard BIOS and the NIC
  13. Guest

    Just lots of thanks for those who took the time to offer answers and
    ideas for my question.

    Between the wisdom of you folks, and some digging on the net, I have a
    handle on it.

    Much obliged,

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