Call routing to an instance of conferencing software

A conference service number system enables the reconfiguration of an existing telephone number as a service number usable for selectively routing calls to each of a client endpoint and a dedicated conference software instance. A conferencing system implements separate conferencing software instances for individual operators for whom unique telephone numbers, are assigned. A telephony system facilitates calls to and from telephone numbers and implements a menu system (e.g. an interactive voice response (IVR) menu) for presenting a caller with options to either route a call to a specific telephone number to the subject operator (e.g., to a client device of that operator) or to a conferencing software instance implemented specifically for that operator. The call is accordingly routed to either a device of the operator or to the conferencing software instance based on the selection by the caller.