★ The GSM's number of frequencies is 124

★ When the operators do not have enough frequencies, the range to be used is CDS 1800

★ Frequency hopping is used when the frequencies used are more with high interference.

★ Frequency hopping is utilized to equalize interference for the frequencies that are used in their range.

★ One of the frequency hoppings is Synthesised Frequency Hopping

★ Synthesized hopping allows the transmitter to change its frequency based on time slots. Because of this process SFH is known as fast hopping.