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Mini or micro SD (SD stands for "Secure Digital") is the most common standard used for data storage in mobile phones. Apart from the data storage, some manufacturers make other accessories that connect to the phone's mini (micro) SD slot. The leader on this market is SPECTEC. SPECTEC offers the following cards and extensions:
* WiFi cards - adds WiFi to PDA
* GPS cards - adds GPS Receiver to PDA
* Bluetooth cards - adds Bluetooth to PDA
* Video-Out - enables PDA to display screen over projector or external monitor
As one can see above, one can add WiFi, GPS, Bluetooth, and even video output to a PDA. Suppose, you are going to a business meeting. Just load all your documents into your PDA, then connect the Video-Out adaptor and you can impress your partners making a presentation from your phone. There are also some other extension cards that enable PDA to implement home automation, to monitor real time health condition and even more. So, if you need one of those functions, just insert the respective card and here you go!
Even if your phone does not use SD standard, still you may use some accessories that connect to phone via Bluetooth. For example, SPECTEC offers a Bluetooth GPS receiver. Using Bluetooth may be preferable even if the phone supports SD cards because in that case SD slot will remain available for data storage.
There are some cards that combine WiFi with data storage. So, one can add WiFi to PDA while still having up to 2 GB of data storage in the card. A common disadvantage of WiFi mini- and micro SD cards is that they are bigger (longer) than standard storage cards, so that the card pops out of the phone's SD slot. That makes it impractical to keep the card inside the phone, however one can insert the card whenever one needs to use WiFi connection.
SPECTEC do not sell their products online, however, one can easily find many online resellers on the Web. There are also other manufacturers of such cards. A good place to search for them is at Amazon.com. So, if you have an older device that does not support all of the new features or, if you have some very special idea in mind, just search the Web for the appropriate extension card to empower your phone the way you want.