Telephony 101

Automated Attendant

No pimply IT hotshot, AA is completely different than IVR.

Call Appearances

Call Appearances is a feature used on many multi line telephone systems or MLTS to allow a single telephone to handle multiple calls at once without having to be bombarded with an annoying call waiting tone.


Central Exchange (or Centrex) is a service provided by many telephone carriers to deliver PBX or Key-like services via the telephone company (or Telco.) Little to no hardware is required at the customer end, unless its special adjuncts for digital telephones for power, etc. Regardless of the hardware, the “brain” lives out in the “cloud” so to speak at the central office. If it’s a government, or a large corporation, rarely are these actually installed on site.

Conference Calling

There’s a difference between three way calling, loudspeaker calls and the ones you hear quarterly by the publicly held companies.

Enhanced 9-1-1 

This three digit telephone number automatically routes callers to a Public Safety Answering Point. What does that mean for you? You may be able to get emergency assistance from police, fire and/or EMS. That’s if you have a) a reliable phone service or b) you know where you are and c) people in the IT department know how your office phone system works. What’s “enhanced”? You get location, number and/or name passed through the PSAP when you call. A “basic 911” is just a hotline in the simple context.

Interactive Voice Response

Want to know how AppleCare works to take your call and you wonder how the agent or the voiceover knows your history of problems with your Mac or iPhone? It’s the magic called IVR. (No it’s not a “digital receptionist”…)


A teletypewriter is a special device that was typically known as the Telecommunications Device for the Deaf or TDD. These devices act as typewriters that can carry special signals to provide text based communications over voice telephone lines. This was the beginning of using data over the telephone lines. The phrase TDD is not encouraged on this inclusive website.

Voice over IP

The Internet is how many people communicate with their fingertips on a smartphone. The Internet Protocol is basically a driver for the computer to communicate to other computers using a similar driver, of a uniform set of instructions on how those computers are suppose to talk to one another. Voice over IP is the idea of having voice “stream” over this IP network (or geeks calling them “stacks”). However IP’s ancestors was invented almost fifty years ago, and those same fathers of the Internet hated the telephony aspect. However not taking notes from telephony (keywords “not taking notes”) and fast forward to the mid 1990s this lead to unintended consequences with the introduction of VOIP and using IP Telephony for VOIP in the 2000s brought a lot of weird things to happen for a user of a telephone, and the eventual death of the century old technology.

Voice Mail 

You think it’s just a modified PC with an application that runs something similar to an answering machine? You may be right, but did you realize that for many years it had a oh and ten record in terms of success? For almost twenty years, voice mail was dead on arrival. History can be seen on the link.