Everything You Ever Wanted to Know About Mobile Phones

I was online with Engaget mobile phone geeks last night and discovered there's a good deal of confusion: where to purchase the latest smartphones, warranty service, SIM cards, etc. So...here's a quickie post to clarify.

1. Until the U.S. catches up, the most sophisticated and powerful smartphones are available from several reliable sources. Phonesource-USA, which does business on eBay and its own website, is an excellent company and continuously offers the latest unlocked GSM phones from Asia, Europe and the U.K. The company ships quickly from Hong Kong and Nevada and I've purchased smartphones from them for years with excellent results.
   
2. Integron Technologies sells an assortment of consumer electronics items, including smartphones. The service and shipping charges are unmatched on eBay.
3. GSMarena.com has the most comprehensive line-up of smartphones I've ever seen. The website also supplies information on mobile device suppliers. You could spend hours reading about the latest phones from all the major manufacturers: Nokia, Sony Ericsson, Samsung, Motorola, to name a few.
4. Warranties? Aha...now's the time to be careful. When a phone manufacturer releases a new model--say one from Sony Ericsson--it's distributed to different parts of the world, based on mobile carrier networks, language, features and other factors. So one version of a Sony Ericsson phone is intended for sale in Asia, another in Europe and another in the U.K. The usual one year warranty on its phones is only valid in the country or region for which the phone was made. If you purchase the Asian version of the new K770i SE phone, for example, repairs are done in Hong Kong. However, unless you live in Asia and deliver the defective phone to SE in Hong Kong, the warranty is not valid. This is changing dramatically with some manufacturers I'll cover next.
5. Nokia is rapidly opening retail stores in the United States to sell unlocked GSM phones that you can use on AT&T Mobility, T-Mobile and a few other GSM carriers in the States. Warranties for phones sold in the U.S. are valid. Expect to see Sony Ericsson and other overseas manufacturers distributing increasing numbers of mobile phones here in 2008.
6. SIMS--those strange looking cards found in GSM phones--contain your account information, number of usage minutes if you've purchased a "pay as you go" SIM and around 200 names and phone numbers that your GSM phone can access. In the U.K., Europe, Asia and elsewhere, mobile phone owners can purchase SIM's to swap in-and-out of their unlocked phones to get the best calling rates in each country--in many cases, much cheaper per minute than a SIM from a U.S. carrier that you use overseas. In Europe, for example, you can walk into a store, purchase a SIM for France or Germany or Norway and also buy a phone. Verizon and Sprint in the U.S. use CDMA technology. No SIMS. Your phone's ESN--a unique code--identifies your phone to the carrier. With CDMA, your carrier programs your phone to work on its network. Which leads us to...
   
7. Locked vs. unlocked phones. As you may know, when you purchase a cell phone plan from a U.S. carrier, the phone you receive is "locked" to that carrier's network. The locking is usually done at the manufacturer's factory when the phone is branded for AT&T or T-Mobile. While most GSM phones can be "unlocked" using software codes and/or cables, some can't. And even if you unlock a GSM phone that was previously locked by the manufacturer, the phone may not fully function correctly on a different network. You may have MMS or WAP or even calling problems, like poor voice quality and dropped calls. That's because each carrier uses roaming partners to provide coverage in areas where they're few cell towers and signal strength and your phone may not be programmed to access roaming partners. That leads us to...
8. Frequencies. They're basically four frequency ranges for world cell phones---850Mhz and 1900Mhz in the U.S. and 900Mhz and 1800Mhz used by carriers outside the U.S. Triband phones usually operate at 900Mhz, 1800Mhz and 1900Mhz; Quadband at 850Mhz, 900Mhz, 1800Mhz and 1900Mhz. That's why quadband phones are usually referred to as "world phones." They'll work on virtually any frequency used by worldwide carriers. New standards in the 1700Mhz and 2100Mhz band are arriving for 3G service, but we'll skip that for now.

Hope that helps. Cellular technology is complex and, until there's a world standard, differences will affect how mobile phones work.