Amazon announced expansion of Alexa Drop In service to the latest generation of Fire HD 8(2017 and 2018) and Fire HD 10 tablet, to make and receive Drop Ins (one-way intercom style communication) and speaker system-like Announcements through home system of Echo devices and Alexa mobile app on the same account, starting from Wednesday.
Alexa Drop In service enables users to instantly connect with Amazon Echo smart speakers and other Alexa-enabled devices for voice or video-based interactions with family and friends via compatible devices, while Announcements feature let you broadcast to all other Alexa devices in your household.
Those wishing to use the new feature will need to enable it on their Fire tablet,
How to Turn On Drop In and Announcements on Amazon’s Fire HD Tablets
Step 1: Go to Settings app > Alexa section.
Step 2: Turn on Voice Assistant, Hands-free Mode and Calling and Messaging in Communications section of the app.
Source: Martyn Landi, Press Association Technology Correspondent: Yahoo Finance: Alexa Drop In functionality to Fire HD tablets