Difference Between Ground Start and Loop Start Signalling in VOIP?

Ground Start Signalling

-->  Requests a new telephone call by grounding two of the wires in the cable temporarily.

--> Must be configured on the Router manually.

--> Typically used When connected to PBX.

Loop Start Signalling

--> Signals by completing a circuit (by lifting the handset off-hook) and dropping the total DC
voltage down on the line.

--> By Default enabled.

-->  Typically used when connecting to analog devices, such as telephones, fax machines, and
modems.

Ref: Cisco Press