A mechanism introduced to allow subscribers on a 4G network to make and receive voice calls. In essence, when a Mobile Originated / Terminated call needs to take place, the subscriber will leave the 4G network and fall back to the 2G/3G network in order to make or receive the call.
Get your weekly dose of telecoms terminology delivered straight to your inbox!
We promise, no spam - just clear-cut telecoms terms to keep you on top of your game.
Our YouTube channel offers over a hundred free videos (and counting!) covering a range of technology topics.
Subscribe to our channel to be the first to know when we release new videos:
Use this no-obligation free trial to get a taste of what it's like to be an Mpirical student.
Included with the trial is an all-access pass to the LearningZone, which contains learning tools and other useful resources to help you make the most of your training.