ETRI) runs on a Linux Smartphone as shown in [23]. Lastly, the UIs should support interoperability among the different resources and applications. The UI should, for example, easily import a scanned copy of a business card into a user's contact list. The picture taken from the mobile camera should also be easy to process and import or export onto relevant applications, such as a photo-album-management application [25]. Power Supply All the wireless devices require power supply to operate. Power may be supplied to the telephone by an internal battery, power line voltage, or other source such as a car battery or cigarette lighter socket. Almost all of today's wireless devices use small rechargeable batteries as their sole power supply source [1]. Battery technology is a key factor in determining device's size, talk time, and standby time. Several types of batteries have been used in mobile phones since its inception in the 1980s namely - alkaline, lead-acid, zinc-air, NiCd (nickel cadmium), NiMH (nickel metal hydride) and Li-Ion (lithium ion). Li-Ion is the most common rechargeable battery that can be found in laptops, PDAs, cell phones, iPods and Smartphones. They are SO common since these are one of the most energetic rechargeable and lightest batteries available today. Some of the key advantages and shortcomings of Li-Ion batteries are as follows [26,27]: 10.7.1 Advantages Lighter than other types of rechargeable batteries. The latest ultra lightweight phones use Li-ON batteries which tend to weigh 30% less than NiMH. Lithium is highly reactive meaning a lot of energy can be stored in its atomic bonds as compared to NiMH and lead-acid batteries. A Li-Ion battery only loses about 5% of its charge per month, as compared to a 20% loss per month for NiMH batteries. Li-Ion cells normally provide 3.6 V versus 1.2 V for NiCd and NiMH cells. Thus, only one-third the number of cells is needed to provide the same voltage. Li-Ion batteries have no "memory effect" that is, these do not have to completely discharge before re