Connect Bluetooth device to an unknown device

Is it possible to connect a Bluetooth device to an unknown device? I thought all Bluetooth devices had to be paired with another Bluetooth device before they could be used together. Someone mentioned a possible application where a Bluetooth device (most likely a Windows Mobile phone as the iPhone SDK doesn't support Bluetooth connections) can be used to say read electric meters in a given area. I thought the phone would have to be paired with each meter before any other communication could take place. Is this correct? Can the phone receive arbitrary data from a Bluetooth provider before they are paired?

From stackoverflow

• If you know the MAC address of a bluetooth device and it is connectable you can talk to it directly.

• Hai Dear,

  I have apple i phone 2g, how to connected bluetooth to other device like iphone to mobile phone

• You don't have to have security set up (no pin code) so you could have a bluetooth device that is always discoverable and will always connect/pair. So this could be used for the 'read a meter' type application.

  Also, in Bluetooth 2.1, you have Extended Inquiry data so you could get the meter reading by having the meter encode the reading into the Extended Inquiry response. Then you don't even have to connect/pair. Just have a device that does an inquiry and gets the data that way.

  There are some new standards coming for BlueTooth for Low Energy devices that would basically act like sensors, which are specifically targeted at this type of application.

  There is more info then you could possibly want at www.bluetooth.org

• Talking to a device, and having it understand what you are saying are two different things.

  The device on the other end of the line must support the function that you are trying to achieve. There's no point sending realtime video to a bluetooth enabled thermostat whose only function is to control and report the temperature.