Some of them also allow you free voice and video calls to your contacts, along with some interesting features and functions that you don't get with traditional GSM text messaging.
Ụfọdụ n'ime ha na-enyekwa gị ohere olu na oku vidiyo na kọntaktị gị, tinyere ụfọdụ atụmatụ na ọrụ dị mma ị na-enwetaghị na ozi GSM omenala.