2G vs 2.5G
Cellular phone technologies are delineated by generations, with each generation having different technologies and different features. If the improvements are not really very significant, there are often characterized as half-steps. This is the case with 2G and 2.5G. The main difference between 2G and 2.5G is the implementation of packet switching, which is what is used in computer networks. The main focus of 2G is to provide voice services and utilize circuit switching mainly.
The advantages that 2.5G provides are a result of the previous difference. Mainly, the increased data speed ranging from 56kbps to 115kbps. Faster speeds are not really needed if you just use your cellphone for voice calling or text messaging. But the increased speeds also opened up a new set of services to the consumers.
Probably the most important service provided by 2.5G is web browsing via WAP. WAP is a simplified version of websites that are necessary because mobile phones back then were unable to render full web pages due to very weak hardware. Although very simple, it still provided a basic level of web interaction that was not available till then.
Another new feature provided by 2.5G is the ability to send and receive photos and videos via MMS, or the Multimedia Messaging Service. This uses the packet switched network, pretty much like the internet to deliver the multimedia content from the one phone to the other. This service is not possible without the new 2.5G technologies.
The jump from 2G to 2.5 is not really a major thing for telecoms because it is just an upgrade over existing 2G infrastructures. It just needs compatible handsets and a few modifications to the base stations. But the new features it implements make it very worthwhile for both the telecoms and the subscribers.
2.5G was classified as such because it did not really provide adequate speed like true 3G does. It also uses the transmitters and other infrastructure of the older 2G networks. 3G typically operates in separate frequencies than 2G and 2.5G uses, thus allowing mobile phones to switch from one to the other when capable.
Summary:
- 2.5G implements packet switching along with the circuit switching in 2G
- 2.5G has much faster data rates than 2G
- 2.5G allows limited web browsing while 2G does not
- 2.5G has MMS services while 2G does not