Stands for Floppy Disk Drive Traditionally refers to the A: \ drive or 1 44 MB (3 5") High Density Floppy format, but can also refer to older 720K (5 25") Floppy drives
In a FDD system simultaneous transmission and reception of radio signal is possible This allows the mobile phone user to talk and listen at the time The mode of communication is facilitated by having a frequency channel with two separate operating frequencies, one for transmission and the other for reception