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A Private Branch Exchange (PBX) is a telephone exchange that serves a particular business or office, as opposed to one that a common carrier or telephone company operates for many businesses or for the general public.
PBXs make connections among the internal telephones of a private organization—usually a business—and also connect them to the public switched telephone network (PSTN) via trunk lines.
Trunk
A trunk line is a circuit connecting telephone switchboards (or other switching equipment), as distinguished from local loop circuit which extends from telephone exchange switching equipment to individual telephones or information origination/termination equipment.
When dealing with a Private Branch Exchange (PBX), trunk lines are the phone lines coming into the PBX from the PBX from the telephone provider. This This differentiates these incoming lines from extension lines that connect the PBX to the PBX to (usually) individual phone sets.
Extensions
A telephone extension is an internal telephone line attached to a Private branch exchange (PBX). The PBX operates much as a community switchboard does for a geographic telephone numbering plan and allows multiple lines inside the office to connect without each phone requiring a separate outside line. In these systems, a dialer usually has to dial a number to tell the PBX to connect with a landline to dial an external number. Within the PBX, the user merely dials the extension number of the person. Each phone line may be extended up to a fixed maximum.
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Secure Call
A Secure CallA secure call is a voice connection which can't be wiretapped and it runs over Voice Over IP (VoIP) communication protocol.
End to Site security model
Secure call is encrypted from client up to server.
The end The end to site security site security model provides a strong security a strong security level and can be used among two or more
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Given that in this security model the server can decrypt secure calls content, it is possible to provides advanced telephony features such as:
- 3-way calls
- call transfer
- conference rooms
End to End security model
Secure call is encrypted from client up to the other client. Despite server relays encrypted traffic, it does not knows the encryption keys, so it cannot decrypt the call content.
The end to end security model provides the highest security level but can be used only between two
equipped devices.Brand brand client
This security model does cannot be used to integrate enterprise PBXs.
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