Why must an EMTA have an internal battery installed?

An EMTA (Embedded Multimedia Terminal Adapter) must have an internal battery installed primarily to qualify as a carrier-class telephone service. This requirement ensures that the device can provide consistent and reliable telephone service, even during power outages. The internal battery allows the EMTA to maintain its functionality, meaning that users can still access telephone services when they are most needed, such as during emergencies. This capability is critical for maintaining the standards expected of telecommunications services, especially for those related to emergency communication and essential connectivity.