GSM vs CDMA Phone – Everything you need to know


CDMA and GSM, two fundamental mobile phone technologies, are incompatible. They’re why old AT&T phones won’t work on Verizon’s network and vice versa. These aren’t the names of any upcoming techno bands. GSM and CDMA are two cellular services, frequency bands. While these letter jumbles may seem strange, they can substantially impact phone carrier selection and phone kind. 

With the development of next-generation networks, your present gadget may have limitations depending on its model. Before buying a phone, you need to know whether your phone is CDMA or GSM, as it can save you from the hassle you make get in the future. 

Here at Talk Home Mobile’s blog on the critical difference between CDMA and GSM phones, we will highlight the significant difference between these two types of cell phones. Furthermore, we will also discuss why GSM cell phones are an ideal suit for those who are looking out for the cheapest ways to make international calls. Here’s all you need to know about CDMA vs GSM, including how the two differ and what to expect in the future. 

What is GSM? 

GSM stands for Global System for Mobile Communications. It’s a form of mobile communication technology that allows several data signals and voices to be transmitted in different time slots over a single communication channel. For transmission, GSM employs FDMA and TDMA technology. 

The Europeans first introduced this digital cellular technology for speech and data signal transmission. The SIM (Subscribers Identity Module) card serves as the main component. Each device in the network has its own SIM card. It means that different GSM technology subscribers can be distinguished by their SIM. Any user can switch between other SIM cards at any time. As a result, they provide additional flexibility. 

In GSM, a tower in any network area serves as a command centre for all mobile devices within a certain radius. This network keeps track of all the devices that use specific SIM card numbers. Signals are transmitted in different time slots using the GSM technology. As a result, the entire channel remains open for signal transmission. Once you’ve made a call to a given number, you won’t be able to make another call to that number. This is because the current signal broadcast has filled the period. 

Every GSM subscriber has their SIM card, an authentication key, a unique algorithm, and unique identity. As a result, billing and network access are tied to the card rather than the device. 

What is CDMA? 

The acronym CDMA stands for Code Division Multiple Access. Qualcomm pioneered it and was initially dubbed IS-95. The CDMA technology allows for full bandwidth utilisation. Every signal is given a unique code before being transmitted over the entire bandwidth of the channel. As a result, different codes distinguish the various CDMA signals that pass over the track. 

Each signal is given its spreading code in the CDMA technology. It aids in the differentiation of distinct movements in a channel. The motion is subsequently detected at the receiver’s end using a set of orthogonal codes. A CDMA station’s base station has several different codes. As a result, when it gets many signals from other base stations, it uses the spreading codes to distinguish between them (these are orthogonal). It eliminates all potential interference by using orthogonal coding. It means that all CDMA users in the network use the same frequency but have different codes. 

The Technology Behind CDMA and GSM Phones 

Multiple-access technologies like CDMA and GSM exist. They’re devices that allow users to jam several phone calls or internet connections into a single radio station. 

The first was GSM. It’s a system of “time division.” The calls alternate. Your speech is converted into digital data and assigned a channel and time slot, so three calls on one track might look like this: 123123123123. On the other end, the receiver merely listens to the given time slot and reconstructs the call. 

When you put a GSM phone near a speaker, the pulsing of the time-division signal produces the infamous “GSM buzz.” That’s essentially gone anymore because 3G GSM isn’t a time division technology. 

CDMA necessitates a little extra computing horsepower. It’s a system of “code division.” Each call’s data is encoded with a unique key before being transmitted all at once; for example, if a channel contains calls 1, 2, and 3, the track will say 66666666. Each receiver has a unique key that allows it to “split” the combined signal into individual calls. 

Because code division proved to be a more robust and adaptable technology, “3G GSM” is a CDMA technology known as WCDMA (wideband CDMA) or UMTS (Universal Mobile Telecommunications System) (Universal Mobile Telephone System). As the name implies, WCDMA requires wider channels than prior CDMA systems, but it has more data capacity. 

(GSM is merely the official term for 2G technology.) However, because the name is also commonly used to refer to any technology on the “GSM route” certified by the same industry authority, I’ll refer to WCDMA as 3G GSM to avoid confusion with the separate 2G CDMA.) 

GSM has progressed quicker than CDMA since its introduction. WCDMA is the third generation of GSM technology. The 3GPP (the GSM governing body) published HSPA extensions, which theoretically boosted GSM network speeds to 42Mbps. 

Meanwhile, our CDMA networks were locked at 3.6Mbps. Faster CDMA technologies exist, but US operators choose to forego them in favour of 4G LTE, which is more compatible with international standards. 

The Difference between CDMA and GSM Phone – A Comparative Analysis 

Difference between CDMA and GSM 

Full form   The acronym GSM stands for Global System for Mobile Communication   The acronym CDMA stands for Code Division Multiple Access 
Basic   Only Sim specific  This one is handset specific 
Availability  GSM is widely available and widely utilised around the world. It is used by about 80% of the world’s mobile networks.  CDMA isn’t widely used, and it’s only available in a few carriers and countries. Canada, Japan, and the United States are the only countries with these devices. 
Technology Used  Time-division multiple access (TDMA) and frequency division multiple access (FDMA) are used (FDMA).  Frequency Division Multiple Access (FDMA) and Time Division Multiple Access (TDMA) 
Data and Voice  GSMA networks support the transmission of both data and voice at least once.  This feature is not supported by CDMA technology. Voice and data cannot be transmitted at the same time. 
Maximum Downloading Speed  The maximum speed of GSM is 384 Kbps (Kilobytes per second).  The top speed of CDMA is 2 Mbps (Megabytes per second). 
How customer information is stored  GSM stores the data on SIM  The data for CDMA is stored in a phone or headset. 
Rate of Data Speed  GSM is slower as it offers 42 Mbps(Megabytes per second) on 3G.  CDMA is faster. It provides a maximum speed of 2 Mbps(Megabytes per second). 
Waves Pulse  GSM phones generally emit a continuous wave pulse. Therefore, you don’t need to reduce its exposure to electromagnetic fields.  CDMA phones don’t have any such wave pulse 
Radiation  The GSM phones emit about 28 times more radiation than the CDMA phones.  The radiations emitted by CDMA devices are comparatively low. 
Flexibility offered  The GSM technology is more flexible when compared to CDMA. You can switch your Sim between multiple devices.    CDMA technology is not very flexible. They make it hard for users to switch Sim between Mobile phones. 
SIM Card  You always need a Sim Card for the working of a GSM Mobile Phone  For a CDMA decision, you don’t particularly need a cell phone. 
Security  GSM technology is less secure.  CDMA technology is more connected.  
Built-in  There is no built-in encryption in GSM phone  CDMA comes with built-in encryption. 
Division  Each carrier of GSM phone is divided into time slots. This means each user gets a different time slot. Moreover, no one can access the came calling space until the ongoing call ends.  CDMA allows each user’s transmission over the entire frequency spectrum. 
Technology to transfer data  Edge technology is used in the case of GSM.  The CDMA technology uses the EVDO ready data transfer technology. Thus, the data transfer, in this case, is high-speed. 
Spectrum  Wedge spectrum is followed by GSM technology.  Spread spectrum technology is followed in the case of CDMA technology. 
Network  The network tower in each cell functions as a mobile phone in that area.  It has a physical channel and unique codes for each device on the network. 
Roaming  GSM is offering worldwide roaming  CDMA is offering limited roaming. 


Advantages of GSM Phone 

  • A more appropriate network with more powerful features. 
  • International calls are free of charge. 
  • There is global connectivity and coverage. 
  • In GSM, the SAIC and DAIC approach provides excellent transmission quality. 
  • Users can easily switch between different types of phones because the phone is based on a SIM card. 
  • GSM signals do not deteriorate in any way. 
  • GSM is simple to integrate with other cellular technologies like CDMA and LTE. 
  • It can use repeaters. 
  • Talk time is often extended due to the pulse nature of transmission. 

Advantages of CDMA Phone 

  • Because CDMA channels are difficult to decode, they provide increased cellular communication security. 
  • In comparison to GSM, call quality is superior, with more constant sound. 
  • Less interference from handoff features minimises call dropout, resulting in improved coverage with fewer antenna sites and lower power consumption. 
  • Increase user capacity by 4 to 5 times above GSM since it has more users per MHz of bandwidth than any other system. 
  • Multipath performance is improved. 
  • The frequency reuse strategy is simpler to implement. 
  • Smaller mobile phones 
  • Most efficient spectrum usage 
  • Low electricity consumption 

Why Choose a GSM Phone? 

GSM phones have more precise signals when making calls indoors and can use cellular repeaters, enhancing and rebroadcast calls for higher signal strength. They also consume less energy, allowing them to be used for extended periods before needing to be recharged. 

Moreover, since GSM phones don’t have any restrictions on roaming, they are a perfect suit for travellers. The technology also supports new services and has an improved spectrum efficiency. Another key feature that makes GSM phones more convenient is the low-cost mobile sets and base stations. 

Switching to Talk Home Mobile 

Get your hands on a GSM phone and use the Talk Home Mobile Sim card to enjoy cheap minutes at the lowest rates across the UK. Starting at just 1p-c per minute, Talk Home Mobile offers blazing fast internet, minutes and messages.  

Buy one of the popular plans by Talk Home Mobile and connect with your loved one in over 240+ destinations, along with roaming coverage when you are out home. Choose an international plan and pay less for your calls abroad – only with Talk Home Mobile. 

Interesting Read: Compare the Best SIM Only Deals (2022): Unlimited Data, Minutes & SMS 


Carriers are beginning to phase out their outdated 2G, and 3G networks as 5G networks go out. GSM and CDMA technologies will become even less relevant as a result. In fact, during the last few years, most major US cellular carriers have been shutting down their 3G networks.  

Verizon has announced that its CDMA 3G network will be decommissioned by December 31, 2022. 1 This affects 3G phones and maybe some 4G phones. If you have an older phone still connected to a 3G network, you should contact your carrier to determine when these networks will be shut down and how it will affect you. 


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