The GSM service system means global system for mobile telephones. GSM systems are used in nearly 200 countries (with 600 million subscribers) worldwide, from Europe (where the standard originated) throughout Africa, Asia and Australasia. The good news for world travelers is that most cell phone manufacturers offer dual-band (900 and 1900 MHz), tri-band (900, 1800 and 1900 MHz) and a growing number of quad-band (800, 900, 1800 and 1900 MHz) phones that will work practically anywhere GSM systems are found.

The CDMA service system means Code Division Multiple Access. It offers some international roaming capability, though nothing like the near-global coverage available from GSM carriers. In actual application, GSM has such widespread following and rich features to keep CDMA from being much of a threat. However, it's entirely possible that CDMA will contribute to the eventual demise of TDMA in the Americas, though that time is likely to be many years away for the US and Canada, and much longer for Latin America.

Each year, these two guys fight for the market shares. However, as for the good quality of China Mobile GSM service system; China Unicom faces the unavoidable challenges.

And more, Like PandaPhone – third part wireless solution provider, it have a China Panda SIM card. This special SIM card is postpaid, no roaming charge, national coverage. The best pet for China different cities trip.

While Post – paid SIM cards are popular among long – term travelers, businessmen, government officers, actors or actress, people who frequently call long –time, and those who need to have a 100% well –connected through communication during their travels.

You can have a whole picture about your call situation, if you do not frequently make calls, a prepaid SIM card is sure enough. However, if you have many calls and frequently run out of minutes, a post-paid SIM card is your first choice.

If you want to calculate the service life, please check the service life first, and then remember the first call date. We are sure you will figure out the correct end date.

Sometimes, your SIM card provider remind you of calling them to activation, they mean they will activate the voicemail or other service in SIM card but not for the basic calling service.

1、Scratch card
Customers can buy scratch cards from Communication service center or dealers and recharge account by calling 13800138000.

2、Electronic recharge tickets
Customers can use electronic card recharge to recharge account at the multi-media self-service terminals of Communication service center or at the Good Easy self-service terminals of subway stations, residence districts, banks, and 24-hour chain stores. Electronic recharge tickets can be recharged by dialing recharge number.

3、Aerial recharge
If you need to use this way to recharge, the recharge fee will be available upon the different dealers. They will send a message to recharge for you by using a special SIM card. If it's recharged successfully, you will receive a feedback from them. The recharge method is the most safety method while you travel around China in that the different cities enjoys different recharge systems.

Recommended free recharge dealers:
www.pandaphone.com
www.refillchinasim.com
www.pandasim.com

Like PandaPhone, most third part wireless solution providers offers this kind of China SIM card, working national China with no roaming charge, quality wireless service.

* The Local coverage for low rate is different.
Beijing SIM card can only enjoys the low rate in Beijing; when travelers out of Beijing, the roaming charge will come into exist. So does Shanghai SIM card.

* SIM card only can be recharged by local (Beijing/Shanghai) recharge card.
If travelers purchase the other city's recharge card, the recharge service fails.

* SIM card enjoys the different promotions.
Different cities have different promotions for SIM card services. Some may have voicemail service; the others may have an inexpensive international IP service.

Due to the large difference between the city SIM cards, third part wireless solution providers offer a China SIM card to cover the differences. This China SIM card work national China, enjoying the low rate no matter where you travel around China.

Many third part wireless solution providers' website have this service. They are 24/7 English customer service, directly recharge, and what's more, there are no differences to them where you purchase the SIM card from. They will give the most convenience solution for you according to your situation. But remember; never forget to leave the second contact number with them. Sometimes, if your cell phone is run out of the minutes and there are some problems with your SIM card, they are able to contact with you in the due time.

Dose the SIM card belong to China Mobile or China Unicom?
China Mobile: purchase China mobile recharge SIM card (mostly, the first three number of China Mobile cell phone is 139, 138, 137, 136, 135, 134(0-8) and 159)
China Unicom: purchase China Unicom recharge SIM card (mostly, the first three number of China Unicom cell phone is 130 or 131)

If your SIM card from China Mobile purchase China Mobile recharge card, if from China Unicom, do China Unicom recharge card.

As for China/Hong Kong Dual SIM card, the coverage is not only national China but also national Hong Kong. However, for this SIM card, the rate in China is as low as China SIM card while in Hong Kong, the rate will be a bit more expensive than Hong Kong SIM card.

Another way to check is call at your SIM card providers; they will do the check for you also with perfect English service.

Another way to check is call at your SIM card providers; they will do the check for you also with perfect English service.

Recommended free recharge dealers:
www.pandaphone.com
www.refillchinasim.com
www.pandasim.com

Recharge card is different; you need to confirm whether it is the right one for your China SIM card. Although it can be found on the corner shops, it is hard to get it anytime when you need it.

From China to US: 001-area code-phone No.
From US (overseas) to My phone: 011-86-your cell phone number
From China to International: 00-country code-area code-phone No.
Domestic calls In China: 0-area code- phone No./direct cell phone No.
Local calls: Direct phone No.

Most small cities share the same area code with each other. But the major cities such as Shanghai, Beijing, and Guangzhou enjoy their own area code, which we call it as city code also. The city code usage like area code, when you make domestic calls, please adds it before the phone number.

The dialing ways should be:
From China to US: 001-area code-phone No.
From US (overseas) to My phone: 011-86-your cell phone number
From China to International: 00-country code-area code-phone No.
Domestic calls In China: 0-area code- phone No./direct cell phone No.
Local calls: Direct phone No.

Most third part wireless solution providers will inform you with this IP code to save more for your travel. What's more, some provider, like ChinaMobilecard.com will serve you with Long distance IP recharge card, which only save more cost for you international calls.

A dual-band phone operates at both the 900 MHz and 1800 MHz spectrum. Dual-band works in Europe, Africa, Asia, Australia, New Zealand and much of South America.
Tri-band - A tri-band phone operates on three frequency bands, 900 MHz, 1800 MHz and 1900 MHz, allowing you to use it in Europe, Africa, Asia, nearly all of North America, Australia and New Zealand.
Quad-band - A quad-band phone allows you to roam almost anywhere globally. It covers the 850 Mhz, 900 MHz, 1800 MHz and 1900 MHz frequency ranges. Many countries in South America only have 850 MHz GSM service while both 1900 MHZ and 850 MHz GSM services are supported in the USA. 99% of all countries use the GSM standard. WE believe eventually GSM will be the only cell phone standard in the world.