This post, by guest blogger Nicholas, tries to answer some questions about what kind of mobile phone is needed if one plans to travel to Hong Kong and China.
If you are the impatient type, here is the summary:
Voice only: unlocked phone with quad band GSM. Quad band GSM includes 900 and 1800 MHz. CDMA phones are not compatible.
3G Data: unlocked phone with 2100 MHZ 3G (HSDPA, HSPA, HSPA+, UMTS, WCDMA). CDMA and EVDO phones are not compatible in Hong Kong.
Below are some more information for travelers.
UNLOCK YOUR PHONE: Majority of phones sold in North America is locked to a carrier. If you want to travel and not paying high roaming fees, get your phone unlocked. Mobile phone stores can unlock for a fee. To be sure it is truly unlocked, insert a SIM card from a totally different carrier and check if the phone complains. A word of caution, if you insert a SIM from a related carrier (e.g. Rogers and Fido are related carriers), the phone may not complain until you insert a Hong Kong SIM card in it, by then it is probably too late. Mobile phone shops should have expired SIM you can borrow to try.
VOICE: Hong Kong uses GSM 900 MHz and GSM 1800 MHz for basic mobile voice services. If your phone is a cheap dual-band or tri-band, chances are these (cheap feature phones) are not useable outside of you home town. Check with GSM Arena to see if your mobile phone has GSM 900/1800 MHz 2G frequencies.
3G DATA FREQUENCY: If you want 3G data, your phone needs to have the correct 3G frequency. 3G is a broad generic term that includes HSDPA, HSPA, HSPA+, UMTS, WCDMA. For travelers, 3G data is quite sufficient. Check with www.gsmarena.com to see if your smart phone has 3G 2100 MHz (Band 1). If your smart phone has 3G 900/2100 MHz, that is even better.
WHY 3G: 3G enables you to send and receive emails, check weather, use public transit apps, use Google Map or Baidu Map (only in Chinese) to look up address or restaurants, send pictures (caution: pictures can consume large amount of data), use Google Translate, make free (or nearly free) phone calls to your home country via Skype, Kik, Viber, Google Hangout, etc., use WhatsApp and WeChat and other social networking apps. Voice calls over mobile data consumes approximately 1MB data per minute.
4G IS FAST: Many SIM card designed for travelers are primarily for 3G. 4G LTE uses different frequencies in different countries. Hong Kong uses 4G LTE in the 2600 MHz (band 7) and/or 1800 MHz (band 3). If you have an unlocked phone with Band 7 or Band 3 LTE, one2free SIM allows you to use LTE and enjoy fast download speed, but be aware that the download speed is so fast that it can drain your data allocation is a short time.
ACCURATE INFORMATION IS ELUSIVE: The information on GSM Arena is typically accurate but not always, you should double check with your phone manufacture website and user manual to see if your smart phone has the correct frequency bands for travel. Unfortunately this information is not readily available because phone sellers and carriers have nothing to gain when you travel and not paying roaming fees. They like to keep you in the dark and trick you to do roaming so they can profit greatly. To complicate things further, the same phone model can have different frequency bands, depending on where the phone was sold.
DO YOUR HOMEWORK, BE REWARDED: If you get your phone unlocked and has 3G (2100 MHz; Band 1), you can insert a Hong Kong SIM card or China Unicom SIM card and travel in style, without draining your bank account.
CHINA UNICOM vs CHINA MOBILE: Short term China Mobile SIM card in Hong Kong typically only supports 2G data. China Mobile in Mainland China has 4G LTE but it is highly unlikely phones acquired outside of China will have the correct frequency band and protocol to be able to use it. China Unicom uses 3G 2100 MHz Band 1 which is compatible with Hong Kong and Europe.
IF YOUR WERE TO BUY A NEW SMART PHONE FOR WORLD TRAVEL: I suggest the Global GMS versions of Motorola G and Motorola G2 because they are (1) factory unlocked and (2) have the correct 3G frequencies for most countries. They are unfortunately not very suitable for short term travel in USA. I will write another post about short term travel in USA. You can buy Motorola G Global GSM version from Amazon.com but they ship to US address only.