Development #1: All New Phone Systems Are VoIP

A closer look at the first item in our list of eight major recent developments and trends in telecom

Telecommunications technology is constantly changing and improving – seemingly faster and faster every year – and at Teracom, we keep our training courses up to date to reflect these changes. In the last post, we identified eight major developments and trends in telecommunications incorporated in our training.

In this post, we take a closer look at the first one: “All New Phone Systems Are VoIP”:

Basic Principle of Operation
The voice entering the microphone is digitized in the near-end phone. Typically 20 ms of digitized voice is packaged in an IP packet, which is carried in an Ethernet MAC frame on copper and fiber LAN cables to the far-end phone. There, the digitized voice is extracted from the packet and used to re-create the voice coming out of the speaker at the far end.

There are, of course, many details not mentioned, including the digitization method, called a codec, the Real-Time Transport Protocol (RTP) that adds timing information, the User Datagram Protocol (UDP) that adds error control and indicates the port number on the far-end phone, and how the bits are represented on copper and fiber LAN cables, to mention a few.

SIP and Softswitches
In a traditional phone system, voice travels on a dedicated circuit to a telephone switch, which physically transfers it to a different circuit to get it to the far end. Not so with VoIP! The near-end VoIP telephone creates a packet addressed to the far-end telephone, then the packet travels over LAN cables and through routers, interspersed with many other packets, to the far-end telephone. The VoIP packet does not pass through a telephone switch. The two VoIP phones exchange packets directly.

So a question is: how does the near-end telephone know what the far-end telephone’s IP address is? This is accomplished with the Session Initiation Protocol (SIP), which implements servers allowing the calling party to find out the IP address of the called party – if the called party wants to accept the call… a privacy shield to prevent Spam over Internet Telephony (SPIT). The servers implementing SIP are called softswitches. They are call setup assistants, and drop out of the picture once the call is established. The phones communicate packets directly.

SIP Trunking
What happens if the two telephones are in different cities? How does the packet move from the near-end VoIP phone to the far-end VoIP phone? One method is to use a gateway to convert the VoIP to an old-fashioned phone call and carry it over PBX trunks and/or telephone company trunks to the far end, where a gateway converts it back to VoIP… but this loses out on the voice-data-video integration synergy of IP communications. Another method is to carry the VoIP packet over the Internet… but there are no quality guarantees on the Internet. A third choice is to pay a carrier to move the VoIP packet from one building to another, as an IP packet, with guaranteed quality. This is called SIP trunking. It should be called VoIP trunking.

That is a thumbnail sketch of VoIP. If you would like to learn more, this is covered in the following Teracom training:

Course 101 Telecom, Datacom and Networking for Non-Engineers
(about an hour out of three days in-class)

Course 130 Understanding Voice over IP
(two days in-class)

The VoIP DVD-Video courses
(3 DVDs, six hours)


“No longer Greek to me! After taking your course, I sat in on a round table at a conference yesterday where VoIP was discussed by Time Warner Cable and Vonage – and I understood most of their diagrams and explanations – something that would have been Greek to me two weeks ago. Thank you!” — Bob Sabin, Tel Control, Inc.

Recent Developments and Trends in Telecommunications

Eight major developments and trends in telecom that you need to know about

Teracom’s training represents the core knowledge set required for the telecom business.  We’ve been teaching people the fundamentals of telecom and networking since 1992, so there have been many changes to the core knowledge set, and updates to our training over the years!

Check out Teracom’s best-of-breed training – with free tutorials!

For the new school year, we have updated our core training yet again, with some significant shifts. For example, Voice over IP is now part of the fundamentals, and channelized systems like T1 and SONET are now referred to as “legacy technologies” for the first time ever.

Here’s a summary of the recent developments and trends in telecommunications that triggered these updates:

1. All new phone systems are VoIP.  SIP trunking services replace PBX / PRI trunks from LECs.

2. Optical Ethernet has replaced SONET for all new core fiber network projects, and is also routinely used for “last mile” connections, achieving a long-held goal in telecommunications: one technology for all parts of the network.

3. MPLS has replaced ATM for traffic management on carrier networks, achieving another long-held goal: convergence and service integration… one network service, one access circuit, one bill for all telecom services.

4. 4G LTE has achieved the goal of a worldwide standard for mobile wireless.

5. “Data” on cellular plans means Internet access. It can be used for phone calls, video on demand, web surfing, real-time traffic on maps or any other application. Cellular data plans can be replaced with WiFi, which is often free.

6. Broadband carriers, also known as Cable TV companies, have evolved into telecom companies, gaining a majority share of residential Internet access in the USA, and providing services to business using both cable modems and fiber.

7. Telephone companies provide Cable TV service using Fiber to the Neighborhood and VDSL over loops in brownfields, and often Fiber to the Premise in greenfields.

8. In the future, the Internet and the telephone network will be the same thing. Basic telephone service will be “IP dial tone”: the ability to send an IP packet to any other point on the network. There will be no such thing as “long distance”.

To explore and understand these developments in more detail, while getting a firm grounding in the fundamentals and installed base…

Join us at famous instructor-led training Course 101,
totally up-to-date with the new-generation network.

“I really appreciated the telecommunications training course provided by Teracom Training Institute. I did learn a lot and understand things better, so that I am now able to tie everything together to understand all the facets of Telecommunications. Many of the acronyms, technologies, network designs and services – I would have no idea what they meant if it were not for this class. Thanks, I really enjoyed it.”
— Natasha White, Comcast, West Chester PA

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