We now have a working phone system with extensions, voicemail, digital receptionists, call queues, and several other features. This is great! However, what if we want to call home or have a customer call us? For that, we need to connect 3CX outside our internal network. This connection is called a trunk. In this chapter, we will cover the following:
Introduction to dial plans (full coverage is in Chapter 6, Configuration)
Hardware needed for analog lines
A Public Switched Telephone Network (PSTN) trunk is an old-fashioned analog Basic Rate Interface (BRI) ISDN or Primary Rate Interface (PRI) phone line. 3CX can use any of these with the correct analog to SIP gateway. Usually, these come into your home or business through a pair of copper lines. Depending on where you live, this may be the only means of connecting 3CX and communicating outside of your network.
One of the advantages of a PSTN line is reliability...