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Glossary of electronic communication and postal services
VDSL - Very high bitrate asymmetric Digital Subscriber Line
Asymmetric transmission technology (which includes the xDSL family) of large bandwidth which allows copper lines, for example in the telephone network, to also be used for high speed data transmission. A VDSL connection uses a high bitate downstream channel (45 Mbits/s), a lower bitrate upstream channel (1.5 Mbits/s), as well as the normal telephone service in the low frequency range.Very Small Aperture Terminal (VSAT)
Satellite communications equipment with a parabolic antenna with a small diameter.VHF - Very High Frequency
One of the frequency bands used for the broadcasting of terrestrial television service.Video On Demand (VoD)
Service which allows a determined programme (according to a catalogue) to be sent to a customer, at the desired moment and in response to an individual request, generally requiring payment, as opposed to the conventional television transmission which is sent to all customers able to receive it.Video-Telephone
Telephone service which also allows the parties involved to see each other in Real Time.Videotext
System which allows the visualisation of text and graphics signals obtained from a central database on video terminals. Broadcast through the telephone network.Virtual calling card service
Service that allows the user to make telephone calls by dialling a specific access code of the National Numbering Plan (''882xy''), with two relevant features: invoicing/collection and mobility. The user is able to make the call after the account associated to the card is identified and authenticated (for example, the number and PIN) based on a set of dialled characters, the account associated to the dialled identification being billed for charges.Virtual Circuit
Connection established between two extremities of the network during a session in which the band width is attributed in a dynamic form and which behaves like a permanent circuit.Virtual LAN (VLAN)
Local virtual network, in which although physically independent the users are connected as if on a local network.Virtual Network
Network with allows connections to be established between various locations without the need for permanent lines dedicated for the exclusive use of their users. The connections are established by means of a programme and exist only during the communication period.Virtual Private Network (VPN)
Virtual private network treated as dedicated lines between these places used by a company or private group to carry out connections between places for voice or data communications. The equipment used remains in the premises of the public telecommunications operator and is an integral part of the public network, but it has software which allows a genuine private network.Virtual Reality
Computerised simulation which allows the user to be present in a virtual environment created by a computer and to interact with the images which are presented as if it were reality. Usually a helmet, glasses and sensory gloves are used.VLAN - Virtual LAN
Local virtual network, in which although physically independent the users are connected as if on a local network.VLR - Visitor Location Register
Register of the location of visitors using a particular mobile communications network to identify the location of the user.VoD - Video On Demand
Service which allows a determined programme (according to a catalogue) to be sent to a customer, at the desired moment and in response to an individual request, generally requiring payment, as opposed to the conventional television transmission which is sent to all customers able to receive it.Voice Mail
Function of recoding a voice message, which can be accessed from various places or equipment. It is available, in the fixed telephone service and in the mobile communications service among others. At a basic level, this service enables the caller to record a voice message in the voicemail box of the user being called when the latter is unavailable, engaged, has activated forwarding to voicemail or does not answer.VoIP - Voice over Internet Protocol
Voice over Internet Protocol - Consists of converting analogue voice packages into digital packages and making them travel on the Internet.VPN - Virtual Private Network
Virtual private network treated as dedicated lines between these places used by a company or private group to carry out connections between places for voice or data communications. The equipment used remains in the premises of the public telecommunications operator and is an integral part of the public network, but it has software which allows a genuine private network.« Back
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