GSM and CDMA Phone- What is the Difference!


GSM Phones

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

The phone itself is not part of the authentication process; the SIM card handles all of that. Also you can 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 common globally, and is used in far more countries than CDMA.

CDMA Phones

Phones running on CDMA networks do not use a SIM card for 2G or 3G, but do still require one for 4G. Electronic serial numbers are used to identify subscribers for 2G and 3G. These serial numbers are coded in to 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 global terms. 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 who continue 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 cuurently support one or more of GSM / AWS / UMTS / HSDPA / LTE  .  North American GSM uses 850/1900 MHz , UMTS/HSDPA 850/1900Mhz, LTE 1700/2600, AWS 1700/2100 frequencies.  Make sure your own phone is compatible with these frequencies.

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

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

A pay-as-you-go SIM card is $10 from most major networks. If you have an iPhone, you can obtain a SIM card from Apple Store in Canada with special pricing. Local calls are $0.30/min and Canada long distance $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 two different technologies used in mobile communication. 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. If you want to switch devices, you may need to contact the carrier to transfer your information.
  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: CDMA, as the name suggests, 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: In general, GSM networks are known for their voice clarity. GSM offers 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 advancements in technology, including LTE compatibility, have improved this aspect.
  6. Carrier Implementation:
    • GSM: Commonly used by carriers worldwide, including AT&T and T-Mobile in the United States, as well as many carriers internationally.
    • CDMA: Historically 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. Additionally, LTE (4G) has 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.