The S III also sports LTE support. Do note that the S III has both 3G and LTE radios, so even on CDMA carriers such as Verizon and Sprint, you can access data and voice services simultaneously (voice goes over 3G, and data over LTE). For the iPhone 5, there's just one radio; if voice is on, data stops if you're using a CDMA network. Ultimately, Verizon and Sprint will have to make the fix on their networks through the introduction of VoLTE (voice over LTE) technology; until then, CDMA-connected iPhone 5 users will notice that apps and services like Find My Friend stop updating when you're talking.
On the other hand, the iPhone 5 is a true worldphone. Even the CDMA models support 3G GSM networks globally, so you can pop in a SIM abroad and get service on your iPhone 5. (Verizon lets you do this in the United States with competing domestic carriers, but AT&T and Sprint do not.) The S III's CDMA models don't have SIM slots, so you can roam only in the few other countries that use CDMA -- at high prices.
The S III and the iPhone 5 are available on nearly all the first-tier carriers in the United States. The iPhone 5 is not available for T-Mobile, though you can use an unlocked or Verizon model on T-Mobile's network -- or you will be able to once the new NanoSIMs that the iPhone 5 is the first to use become available. If you have a MicroSIM from a previous phone or your iPad, it won't fit in the iPhone 5.
The iPhone 5 uses a new connector called Lightning for charging, syncing, and peripheral access. The cable has an embedded chip that assigns functions to each of the eight pins based on what it is connected to. That saves space and will let Apple add capabilities not anticipated today, which the old 30-pin Dock connector could not so easily do. But it also means the end of the cheap-cable era because the new connector is no longer solely a set of physical wires and pins. Also, the $29 adapter for existing 30-pin cables doesn't work with many peripherals, including anything that uses video-out, such as projector and monitor cables, or tries to control the music player, such as some stereos. Until new cables become available, the iPhone 5 is less connectable than previous models. Basically, you can't use an iPhone 5 to give presentations or do screen sharing today, but it will gain that capability in the future.
The Galaxy S III has just a MicroUSB port, which is fine for syncing and charging. But it doesn't support other kinds of peripherals, such as video-out connectors and musical instruments (two areas where the Apple iPad is often used). Although there's no MiniHDMI jack in the S III to connect to monitors and projectors, Samsung's proprietary MHL (Mobile High-Definition Link) cable lets you connect to an HDMI device such as a TV to mirror the smartphone's screen or relay video. But you can't connect to VGA or DVI displays this way. The S III is limited to screen sharing with just HDMI devices, which rules out most projectors.
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