Update and improve introduction in zha.markdown

source/_integrations/zha.markdown

@@ -73,15 +73,15 @@ In addition, it has support for "Zigbee groups" that enable native on-device gro
 
 ## Introduction
 
-ZHA {% term integration %} is a Zigbee gateway implementation that follows the standard Zigbee 3.0 specification (and earlier revisions). In Zigbee, there are three different device types: Zigbee Coordinator (ZC), Zigbee Router (ZR), and Zigbee End Device (ZED). A Zigbee network always has one (and no more) Zigbee Coordinator, however, a Zigbee network can have multiple Zigbee Routers and multiple Zigbee End Devices.
+This ZHA integration is a hardware independent Zigbee gateway implementation that can replace most proprietary Zigbee gateways/bridges/hubs/controllers. It supports pairing/joining devices that use the Zigbee 3.0 standard and earlier Zigbee standards for home automation and lighting. It follows the Zigbee PRO specification, a low-power wireless communication protocol using small digital radios to create a private Zigbee network mesh that can connect compatible devices within a local area.
 
-A Zigbee Coordinator is the central device in a Zigbee network that manages and controls the network. It acts as a physical interface for the Zigbee wireless protocol, as well as being responsible for maintaining the Zigbee network topology and ensuring secure and efficient communication between Zigbee devices. Zigbee Router devices are mains-powered and will act as Zigbee signal repeaters within the Zigbee network mesh to extend its range and improve coverage, while Zigbee End Device devices are usually battery-operated sensors that will not act as Zigbee signal repeaters.
+Before installing the ZHA integration in Home Assistant, you need to connect a Zigbee Coordinator radio adapter, that will act as the physical network bridge interface and single point of security controller for your Zigbee network. Those normally come in the form of a USB dongle that plugs directly into the same computer that is running your Home Assistant installation. The ZHA integration is compatible with many different "Zigbee Coordinator" adapters from various manufacturers. Be sure to [note the recommendations in the respective sections below before buying a Zigbee Coordinator](#compatible-hardware). A Zigbee network always needs to have one Zigbee Coordinator (it can never have more than one), and Zigbee devices can never be connected to more than a single Zigbee network, however, a Zigbee network can have multiple "Zigbee Router" devices and "Zigbee End Device" products.
 
-In the case of ZHA, the Zigbee Coordinator is a radio adapter or hardware module, that contains a microcontroller that runs the Zigbee protocol stack which the ZHA {% term integration %} uses to manage and communicate with a Zigbee network and its devices.
+Once ZHA has been set up with a Zigbee Coordinator it will automatically create a Zigbee network and you will be able to join/pair any Zigbee Router devices and Zigbee End Devices. With only a few [limitations](#limitations), most devices will join/pair directly regardless of brand and manufacturer. It is generally recommended to buy Zigbee 3.0 compliant devices if possible because those offer better interoperability, though a new Zigbee Coordinator is also backward compatible with older devices as well. Still, be aware that [all functionality might not always be supported or exposed for every device out-of-the-box](#knowing-which-devices-are-supported) as some devices that use manufacturer-specific extensions to add non-standard functions and features could sometimes need [device-specific code to fully work with ZHA](#how-to-add-support-for-new-and-unsupported-devices).
 
-Before installing the ZHA {% term integration %}, you will need to buy and connect a Zigbee Coordinator radio adapter or hardware module, those usually come in the form of a USB dongle that plugs directly into the computer that is running the Home Assistant installation. The ZHA {% term integration %} can work with many different "Zigbee Coordinator" adapters, however, be sure to read the respective sections below about compatible Zigbee radio adapters and hardware modules.
+Because a Zigbee relies on "mesh networking" technology it depends heavily on having [Zigbee Router devices](#using-router-devices-to-add-more-devices) to expand the network coverage and extend its size. These are always mains-powered devices that route messages to other devices that are located close to them within the Zigbee network mesh to improve the range and increase the total amount of devices you can add.  You should therefore make sure that you add many Zigbee Router devices and not just Zigbee End Devices or else its network mesh connection routes will be limited due to the short range and poor wall penetration of Zigbee radio signals. It is highly recommended that you read and follow all the general tips below about [Zigbee interference avoidance and network range/coverage optimization)](#zigbee-interference-avoidance-and-network-rangecoverage-optimization).
 
-Once ZHA has been set up and the Zigbee Coordinator radio adapter or module is configured, you will be able to directly join/pair any Zigbee device to the Zigbee network; regardless of the manufacturer and brand of that Zigbee-based product. Note, that while it is generally recommended to buy Zigbee 3.0 compliant devices as those should, in theory, offer greater interoperability, be sure of the sections about which devices are supported and exception handling.
+Optionally you can configure Zigbee grouping of lights, switches, and fans (i.e. support for commanding multiple devices as a single group). In addition, you also have the [option to bind some Zigbee devices](#binding-and-unbinding), like binding a button on a remote control directly to a device or group (i.e. define relations between two or more Zigbee devices that will work even when the Zigbee Coordinator and ZHA integration is not available).
 
 ## Compatible hardware