Nokia Data Communication Techniques

Nokia phones use two types of communication methods for data transmission and communications with the PCs: FBUS and M2BUS. Sending ringtones and graphics to a phone depends on whether it uses FBUS or M2BUS 

M2BUS:
Uses 5 pins
Half-duplex comms
Used in Nokia 21xx phones (data comms only)
Used for service and adjustment purposes 
Up to 2Mbps bursty internal data speeds over the cable connection


FBUS:
High speed full-duplex communications between phone and PC
Nokia Data SuiteTM v1.x and v2.x application uses only the FBUS transmission method
Used in Nokia 3/5/7/8/9 series phones
Used for data comms at 9/6/14,4kbps to GSM network and PC
Used for service and adjustment operations