Final answer:
Digital phones can continue to work during a transition to VoIP with the help of specialized gateways that convert signals between the old circuit-switched system and the new packet-switched VoIP network.
Step-by-step explanation:
During the migration from a circuit-switched PBX (Private Branch Exchange) to VoIP (Voice over Internet Protocol), digital phones may continue to function with new VoIP equipment and services via specialized gateways.
These gateways serve as an interface between the circuit-switched network and the packet-switched network used by VoIP. They convert the digital signals from the traditional phone system into packets that can be sent over the Internet or a private network.
VoIP gateways also provide the inverse functionality, converting incoming VoIP calls into a format understandable by digital phones on the circuit-switched network.
This allows businesses to transition to VoIP at their own pace without having to replace all of their existing telephony hardware immediately.