FAQs 

GSM and CDMA Phone- What is the Difference!

David Tremblay
GSM

GSM Phones

GSM phones use a SIM card for 2G (voice and text), 3 G (voice, text and internet), and 4G (high-speed internet and VoLTE) operation. This small, removable plastic card stores the data needed to identify a subscriber on a wireless network.

The phone is not part of the authentication process; the SIM card handles everything. You can also remove the SIM from your current phone and insert it into another compatible device, provided it’s either with the same carrier, or you’ve ‘unlocked’ it from its original network for use on another.

Swapping the SIM means the new phone will operate over the same network with the same phone number. GSM is a global standard used in far more countries than CDMA.

CDMA Phones

Phones on CDMA networks do not use a SIM card for 2G or 3G, but they still require one for 4G. Electronic serial numbers are used to identify subscribers for 2G and 3G.

These serial numbers are coded into the phones themselves, which creates a problem. You will need to get your new provider to grant permission for your device to be given a serial number and, thus, a working service line and phone number on its network. This permission is not often granted.

CDMA is not nearly as common as GSM in terms of global usage. Travelling with a CDMA phone may be difficult. As for 4G and 3G, both carriers use LTE and HSPA+, respectively.

Canadian networks stopped supporting CDMA phones in May 2016.  United States carriers using CDMA after that date include Sprint and Verizon.  United States carriers which use GSM include AT&T and T Mobile.

Rogers, Bell, Telus, WIND, Mobilicity, SaskTel and Videotron – run on GSM Network

GSM Phones

All networks in Canada currently support one or more of GSM / AWS / UMTS / HSDPA / LTE. North American GSM uses 850/1900 MHz, UMTS/HSDPA 850/1900Mhz, LTE 1700/2600, and AWS 1700/2100 frequencies. Make sure your phone is compatible with these frequencies.

To be compatible, you must have a tri-band or quad-band GSM or 3G phone supporting 1900 MHz. AWS phones (other than the Google Nexus) are not usually sold outside North America. LTE from outside North America is not compatible, but these phones have generally GSM/3G frequencies that are still compatible.

Using a local SIM card must be UNLOCKED if your phone is compatible. Phones are usually locked, so you can only use them with a SIM from the service provider or carrier that supplied the phone. Phones can be unlocked to accept  SIMs from other carriers.

A pay-as-you-go SIM card costs $10 from most major networks. If you have an iPhone, you can obtain a SIM card from the Apple Store in Canada at a special price. Local calls are $0.30/min, and long-distance calls in Canada are $0.40/min.

Difference between GSM and CDMA Phone

Difference between GSM and CDMA Phone
Difference between GSM and CDMA

GSM (Global System for Mobile Communications) and CDMA (Code Division Multiple Access) are mobile communication technologies. The main difference between GSM and CDMA lies in the way they handle voice and data:

  1. Network Architecture:
    • GSM: GSM uses a SIM card (Subscriber Identity Module) to store user information. This SIM card can be easily transferred between GSM devices, making it simpler for users to switch phones.
    • CDMA: CDMA does not use SIM cards. Instead, user information is stored on the device itself. You may need to contact the carrier to transfer your information if you want to switch devices.
  2. Technology and Standards:
    • GSM: GSM is based on Time Division Multiple Access (TDMA) technology. It divides the signal into time slots, allowing multiple users to share the same frequency.
    • CDMA: as the name suggests, CDMA uses Code Division Multiple Access. It assigns a unique code to each conversation, allowing multiple users to share the same frequency simultaneously.
  3. Compatibility:
    • GSM: GSM is more globally compatible. If you have an unlocked GSM phone, you can use it with different GSM carriers worldwide by swapping out the SIM card.
    • CDMA: CDMA phones are typically carrier-specific. While some CDMA phones may have a SIM card slot for LTE (4G) connectivity, they may not be as interchangeable between carriers as GSM phones.
  4. Voice and Data Quality:
    • GSM: GSM networks are generally known for their clarity of voice. They offer better voice quality, especially during voice calls.
    • CDMA: CDMA tends to have better call quality in areas with a weak signal or during a high network load. CDMA can often maintain better call quality under challenging conditions.
  5. Roaming:
    • GSM: GSM networks have better international roaming capabilities due to the widespread adoption of this technology globally.
    • CDMA: CDMA networks traditionally had more limitations regarding international roaming, but technological advancements, including LTE compatibility, have improved this aspect.
  6. Carrier Implementation:
    • GSM is commonly used by carriers worldwide, including AT&T, T-Mobile in the United States, and many carriers internationally.
    • CDMA: Historically, it has been used by carriers like Verizon and Sprint in the United States. However, some CDMA carriers are transitioning to LTE for voice and data.

It’s important to note that technological advancements have led to convergence in recent years, with many modern smartphones supporting both GSM and CDMA technologies.

LTE (4G) has also become a common standard for data across both GSM and CDMA networks. As a result, the strict distinctions between GSM and CDMA are less pronounced in newer devices and networks. When choosing a phone, it’s essential to consider the specific carrier’s technology and compatibility requirements.