• Jim Courtney


While every attempt has been made to focus on the personal user experience while avoiding reference to technology terms and background, occasionally there are some terms that creep into any conversation or discussion about Skype that may need some clarification. Hopefully this Glossary provides some of that clarification.


Mobile Phone Voice Quality Voice Call High Quality Video Public Switch Telephone Network 
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While every attempt has been made to focus on the personal user experience while avoiding reference to technology terms and background, occasionally there are some terms that creep into any conversation or discussion about Skype that may need some clarification. Hopefully this Glossary provides some of that clarification.

3G – A term related to the speed of a wireless carrier’s data service; means the carrier uses a third generation protocol that is significantly faster than 2G/EDGE protocols. HSPA and HSPA+ are faster enhanced versions of 3G. The most common protocol offered by wireless carriers after 2011; mobile phones offered in 2011 or later support at least 3G protocol.

4G/LTE – A term related to the speed of a wireless carrier’s service; means a fourth generation protocol that is faster than 3G. Gradually introduced by carriers over the 2012−2014 time frame. Requires mobile phones that can support 4G/LTE; these include most phones launched during or after 2013. LTE is also the first protocol that is a common worldwide standard with a migration path from carriers who offered either GSM 3G or CDMA 3G.

Audio Terminology − Relates to the audio quality of a voice call resulting from limitations imposed by the connection between the parties on a call. As a guideline keep in mind that our ears can respond to (or hear) frequencies from 50 Hz to 22 KHz; the broader the audio frequency range supported in a voice call, the better the voice quality.
  • Narrowband: Has been used by the landline carriers for decades resulting in the deterioration of voice quality when making a PSTN call relative to speaking face-to-face. Frequency range: 200 Hz to 3700 Hz (3.7 KHz); only captures the “fundamental” frequencies of your voice.

  • Wideband: Used by Internet-based voice applications where there is a direct Internet connection between the parties on a call (i.e., the call does not go through a landline or mobile carrier at any point). Provides much better voice quality due to picking up the “harmonics” of your voice; frequency range ∼100 Hz to 7.5-8 KHz. Results in fewer “can you repeat that” and clearer handling of accents.

  • Superwideband: Was initially introduced with the launch of Skype’s SILK voice technology. Provides the crystal-clear audio quality heard on any Skype-to-Skype call, including video calls. Frequency range: ∼50 Hz to 12 KHz.

Carrier – A more technical term for a traditional phone company that connects and carries landline and/or wireless (mobile) voice conversations. Rogers, Bell Canada, Telus, AT&T, Verizon, British Telecom (BT), and Deutsche Telecomm are examples of carriers.

HD Video − Equivalent of one of two HDTV video resolutions: 720p (1280 × 720) or 1080p (1920 × 1080). HD Video resolutions require faster upload speeds than High Quality Video.

High Quality Video − Video delivered at 640 × 480 resolution and 24 frames-per-second.

Internet Bandwidth − Refers to the speeds at which data is delivered over an Internet connection, with separate download and upload speeds. Usually the download speed is significantly higher than upload speed but they may become close to equal on, say, fiber-based connections. For Skype the minimum and recommended speeds are:

Call Type

Minimum download/upload speeds

Recommended download/upload speeds





128 kbps/128kbps


High Quality Video

400 kbps/400kbps


HD Video



Group Video  (3 participants)



Group Video  (5 participants)



Group Video  (7+ Participants)



Over-the-Top (OTT) Communications − Text, voice, and video communications services that are carried directly between PCs and smartphones using the inherent Internet infrastructure for transporting data packets, bypassing the traditional landline and wireless carriers as service providers.

PC or Personal Computer – Any desktop or laptop computer that uses the Windows, Mac OS X or, in some cases, Linux operating system.

Peer-to-Peer − An Internet software technology where two or more parties are connected directly (without any “server” support) to carry out a transaction or real time conversation. This is the core technology that allows Skype-to-Skype calls and conversations to be “free”; it has also been used for file sharing.

POTS – Plain old telephone service (see PSTN).

Presence – An indication of your current status for receiving Skype calls: Online, Away, Do Not Disturb, Offline, etc. that is seen by your Skype Contacts in the Skype Contact directory within their Skype client. On Android, BlackBerry 10 and Windows Phone devices presence only has two options: Available, Invisible.

PSTN – Public switched telephone network. The legacy landline and wireless voice communications services where calls are essentially made by dialing a number comprising a country code, area code, and local number.

Roaming charges − Wireless carrier fees for use of a smartphone over carrier networks outside the user’s “home” network. Usually quite expensive relative to the charges for the same services on a user’s home carrier network.

Skype – A real-time communications software application that takes advantage of the Internet’s underlying technology to support free or low cost text, voice, and video conversations worldwide.

Skype Account – Manages your Skype subscriptions and “Pay-As-You-Go” payments (call phones, SMS messaging) and calling features such as voice mail, call forwarding, callerID, Skype To Go numbers, and Skype Online number(s).

Skype Client – The Skype software application installed on a PC, smartphone, tablet, or other device.

Skype Credit – Skype’s “currency” used for prepaying for SkypeOut calls, SMS messages, and other offerings on a “Pay-As-You-Go” basis. Fund your Skype Account with Skype credit in amounts of $10.00 or $30.00 or similar amounts in other currencies. Credits are then used as you make calls that require a “per call” payment. (Check out Skype Calling Plans for fixed cost subscriptions.)

Skype Online Number – A phone number that can be called from a landline or mobile phone (PSTN) to reach a Skype user on a Skype client.

SkypeOut – The Skype offering that allows you to make calls from a Skype client on a PC, mobile smartphone, tablet or other device to landlines and wireless phones (or to the PSTN). Charges and calling plan subscriptions apply. Now called “Calls to Landlines and Mobile Phone”.

Skype Profile – Your personal registration information directly associated with your Skype activity: SkypeID, Picture (Avatar), First Name, Last Name, and many optional items, including Location (City, Country), Home/Work/Mobile phone numbers, website address, time zone, birthday, etc.

Smartphone – Any mobile phone that can supports applications that require the Internet for delivering and receiving information in the form of data delivered by a wireless carrier. Often referred to as a mobile PC, due to the proliferation of applications now available for smartphones.

VoLTE – with the availability of very fast 4G/LTE carrier services for data, Voice over LTE will use the data channel to complement or even replace the legacy voice channel. With VoLTE support carriers can take advantage of superwideband audio for significantly improved voice quality.

VoIP − Voice Over Internet Protocol. This is the generic term for the technology behind the ability to place voice (and video) calls over the Internet. It involves digitizing a voice (or video image) at the sending end for transmitting the audio (or video) content over the Internet and decoding the digital information back to an audio voice or video image at the receiving end, all in real time.

WebRTC – An evolving technology to allow chat, voice and video conversations to be launched directly from a website or web application, In effect it would support these conversations without the need to use a separate client or application.

Wi-Fi – An unregulated wireless protocol that allows connections to the Internet over a short range (less than 50 meters) from a Wi-Fi access point. Used for connecting Wi-Fi−enabled PCs and devices to the Internet via local area networks (at home or a business operation) or Wi-Fi hotspots at airports, restaurants, coffee shops, hotels, and other road warrior locations. Often referred to as the “stealth” carrier as Wi-Fi is usually associated with free or low-cost wireless Internet connections that can be substituted for expensive wireless carrier roaming connections when traveling outside the home country.

Copyright information

© Jim Courtney 2015

Authors and Affiliations

  • Jim Courtney
    • 1
  1. 1.OntarioCanada

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