A lot of guides for voice and video assume you already know the basics. So, here, we’re going to cover this to get you going faster. Let’s start with a little history... Phone calls used to use a switchboard in a telephone exchange. Over time, these became a much smaller device called a PBX or PABX. Copper phone lines (PSTN) would connect, and it would route calls. Eventually, we started adding digital ISDN lines. After a while, phone and data networks were combined. This was the birth of Voice over IP (VoIP). The heart of this is the IP PBX, which manages calls. Calls come in over PSTN, ISDN, or SIP Trunk. There can be a phone on every desk, or even a softphone (a software phone running on your laptop). A simple phone system has a PBX, a SIP trunk to a provider, one or more switches, phones, and a DHCP server. The switches power up the phones with PoE, and provide network information with CDP or LLDP. The DHCP server gives the phone an IP, and tells it how to find the PBX. Overview of this video: 0:00 Introduction 0:26 From Analogue to Digital 2:56 Unified Communications 6:52 A Simple Phone System Patreon information: https://networkdirection.net/patreon/ Further Reading: What is a PBX Phone System and How Does it Work? https://www.3cx.com/pbx/pbx-phone-system/ PBX vs PABX: Is there Really a Difference? https://www.telviva.co.za/hosted-pbx/pbx-vs-pabx-really-difference/ What is DID? https://www.3cx.com/pbx/did/ What is a SIP Server, and How Does it Work? https://www.3cx.com/pbx/sip-server/ How it Works - SIP Trunking https://business.mynetfone.com.au/phone-systems/sip-trunking/how-it-works SIP Trunking Explained https://www.3cx.com/pbx/sip-trunking/ LET'S CONNECT 🌏 null 🌏 https://twitter.com/NetwrkDirection 🌏 https://www.patreon.com/NetworkDirection 🌏 https://www.networkdirection.net/ #NetworkDirection #networking #voip