- Public Switched Telephone Network (PSTN) allow users to make landline telephone calls to one another. The call is placed after it is routed through multiple switches. These switches are found in a central office (CO). Ultimately, voice signals are able to travel over the connected phone lines.
- Trunk lines are used for connecting a private branch exchange (PBX) to a telephone service provider. Like, how many trunk lines you have that many no of calls you can make/receive at a time.
- PBX is a server that routs the calls. In this you can program how you want people to be able to call out.
- hunt group is a method of distributing phone calls from a single telephone number to a group of several phone lines. Specifically, it refers to the process or algorithm used to select which line will receive the call. Like, if any no is busy it'll transfer to another no.
- Voicemail deals with voices.
- Auto-Attendant is a term commonly used in telephony to describe a voice menu system that allows callers to be transferred to an extension without going through a telephone operator or receptionist. The auto-attendant is also known as a digital receptionist.
What Does PBX Do ?
- Use of more than one telephone line in an organization, and management of outgoing and incoming calls.
- Splitting of one single phone line into several internal lines, which are identified through three or four-digit numbers called extensions, and switching calls to the appropriate internal line. This saves the organization from having to pay for several lines, and allows all departments to be reached through one single phone number.
- Allow free phone communication within the organization.
- Ensure good interface with customers through features like call recording, voicemail etc.
- Automation of response to calling customers with IVR (interactive voice response) whereby the system can automatically direct users to the most appropriate line through voice menus. It is the kind of feature where, as a caller, you hear things like "Press 1 for the Finance Depart, Press 2 for complaints..." etc.
Disadvantages :
- It is more expensive (For small organizations).
- It is more complicated and stressful.
- It is a single point of failure which means more down time.
- Requires additional employees to maintain and manage the system.