VoIP Terminology

Some of the terminology used in VoIP telephony can be a bit confusing, below I attempt to explain some of the VoIP terminology and phrases that you may come across when people are talking about Voice Over IP.

Not all of the terminology below is exclusive to VoIP telephony, some of the VoIP terminology that  I discuss is equally as relevant when talking about traditional analogue phone systems.

VoIP Terminology Explained

VoIP - Voice over IP. Used to describe a phone system which used the Internet as its underlying transport. Probably the most widely known VoIP system is Skype.

Analogue Phone Line - The normal BT phone system that we use in our house, so called because it uses analogue rather than digital technology.

POTS - Plain Old Telephone System. See analogue Phone Line above.

PBX - Private Branch Exchange. The term traditionally used for a internal company phone system. This is the control element which allows you to make and transfer calls and typically included facilities like; Voice Mail, Music on Hold, Conference Calls etc.

PSTN - Public Switched Telephone Network.  The term traditionally used for the Telephone System.

PCM - Pulse Code Modulation.  The process of digitising an analog signal (human speech).

RTP - Real-time Transfer Protocol.  The protocol used by a VoIP system to transmit the the packets over an IP network. RTP is a send and forget streaming protocol.

MOH - Music On Hold. Typically annoying music or announcements which get played when you are waiting for the person you want to speak to.

Auto Attendant - An Auto Attendant, sometimes also called a Virtual Receptionist, is a simple announcement and menu system to handle call routing. It would normally be something like:

Thank you for calling AKCSL, a leading provider of Systems Management Solutions. For Sales Press 1, for Technical Support Press 2, for all other enquiries Press 3.

The auto attendant messages can either be recorded or can use Text-to-Speech to read out your message. Typically people use Text-to-Speech whilst they are sorting out their menu structure and then record a professional version once they are satisfied with the final structure and message.

Cloud Based - Used to describe a service which is hosted in the Internet, rather than you having a physical device. i.e.

• Cloud Based Computing where you use the processing power of an Internet based Server rather than a system in your office.
• Cloud Based Storage where your data is stored somewhere in the Internet. The Microsoft SkyDrive is a good example of Cloud Based Storage.
• Cloud Based PBX, like the Voiplicity solution we sell, where you use the facilities of a hosted telephone exchange to create a ‘virtual’ PBX for all of your users. i.e. You do not have a physical phone exchange in your building but you still have the full features of an Office phone system,without the cost.

Hunt Group - Where a caller dials a single number and a group of phones ring, the call is then answered by the first person to pick up the phone. i.e. Ring all the phones in the support department or Sales department and any free agent can pick up the call.

CLI - Call Line Identification. This is where the phone number of the person calling you is displayed on your phone. If you use a CRM system it is possible through CTI to automatically pull up the CRM record for the calling number.

CTI - Computer Telephony Integration. CTI allows your phone system to interact with your computer applications, so you can do things like:-

• Dial direct from Outlook
• Highlight phone numbers on websites and then Click to Dial
• Open CRM Records when customers call your office

DDI - Direct Dial In. The name given for the facility where a customer can directly call your desk phone, rather than calling the office number.

Click to Dial - The name given for the facility where you can highlight a phone number within a web page, or web application like CRM, Accounts etc, and then automatically dial the number.

Call Me Now - The name given for having a button, or link, on your website. When the customer clicks on the link they will be asked to enter their phone number. Once they click on OK their phone will be dialed by your phone system, at the same time as your phone is dialed. The customer gets to talk directly to you, at no charge to themselves, when they are ready to buy or ask for further information.

Call Parking - a feature that allows you to put a call on hold at one telephone set and then pick the call up and continue the conversation from any other telephone set.

Soft phone - A softphone is an application which runs on a computer that allows you to make and receive calls, using a VoIP phone system. Typically used with a headset to help improve the call quality. Skype is an example of a Softphone application.

IP Phone - Sometimes called a VoIP phone, this is a phone which connects to a standard data network, rather than the BT phone socket.

SIP  - SIP Stands for Session Initiation Protocol and is one of the protocols that can be used during the setup phase of a VoIP phone call.

VoIP Terminology for Call Quality

Silence Suppression  - Silence suppression is a well-known bandwidth optimisation technique employed by VoIP devices, where packets are only sent if the speaker is actually speaking . This can reduce the total bandwidth required by more than 50%, since most conversations are only one-way at any given time, so the listener need not send any packets while the other party is speaking.

QoS  - Quality of Service provides priority including dedicated bandwidth, controlled jitter and latency (required by some real-time and interactive traffic), and improved loss characteristics. It also ensures that providing priority for one or more flows does not make other flows fail.

Jitter - Variability in the rate at which the sent packets are received. i.e. some packets may get delayed on the network so there is a delay before they are received and recombined to recreate the original call. Jitter shows up as a ‘choppy’ call with people sounding a bit like a Dalek.

Latency - Latency is the time difference between when a packet is sent and when it reaches its destination. All networks experience latency, however for a VoIP network you do not want a high latency (more than 150ms)

MOS - Mean Opinion Score. MOS is a number between 0 and 5 and is a measure of the quality of the call. A MOS of 3.6 is acceptable, a MOS of 4 or above is excellent. A MOS of anything below 3.2 will be of noticeably poor quality.

R Factor - R factor is another way of expressing call quality. R Factor is a calculated value, between 0 and 100, and the maximum achievable R Factor for a given Codec will always be below 100.

VoIP Terminology for Call Security

Listed below is some of the VoIP Terminology which relates to the call security of VoIP phone calls.

SRTP  – Secure Real-Time Transfer Protocol. SRTP is ideal for protecting VoIP traffic because it has a minimal effect on call quality. For each call you make, a unique encryption key is created, which makes eavesdropping almost impossible. This attribute alone makes SRTP a good choice for day-to-day calls, as well as highly confidential conversations.

TLS – Transport Layer Security. TLS is a way of encrypting VoIP calls. TLS encrypts VoIP data traveling between two applications.  The aim of TLS is to keep unauthorised parties from interfering with or listening to calls, and is almost impossible to manipulate externally.

Can I Run VoIP on my Network?

To Test if your network is suitable for running VoIP you should run a set of network tests, follow the links to Speed Tests and Ping Tests in other posts on Computer Spot in order to find out if your network is suitable for VoIP. For businesses other than a sole trader we recommend that you have a separate ADSL line to run your VoIP Phone System.

Books about VoIP & VoIP Terminology

If you are interested in finding out more about VoIP and VoIP Terminology then take a look at some of the books available on Amazon.

Who should I use for my VoIP for Business supplier?

Call Me Now

Click on the Call Me Icon, on the left, and enter your phone number and we will call you right back to discuss your requirements. Call Me is a standard part of the Voiplicity phone system, so is something that you will be able to do on your website with just a few mouse clicks.

In the UK we can provide one of the most cost effective VoIP for business solutions. To find out more about VoIP for Business in the UK contact SystemAssure and we can show you Voiplicity in action.

More VoIP Terminology

If there is additional VoIP Terminology that you want explaining then let us know and we will add it to our list of VoIP Terminology.

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