★ Most popular standard for mobile telephony systems, originated from Group Special Mobile

★ The ubiquity of GSM enables the international roaming arrangements among mobile phone operators.

★ Both signaling and speech channels are digital, and thus GSM is considered as 2G mobile phone system.

★ GSM standard benefited customers the ability to roam and switch carriers without replacing the hand sets and network operators.

★ GSM implements low-cost implementation of Short Message Service