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Introduction
Published in P. S. Neelakanta, ATM Telecommunications, 2018
The interconnection between end-users of telephony, enabled by a set of switching offices in between, constitutes a telephone network. The analog telephone network hierarchy, (popularly known as the Bell system hierarchy) was conceived to interconnect the subscribers through a hierarchical set of switching offices in a tree-like fashion. Each subscriber line (called a local loop) of the local service area was terminated at a local end-office (designated as a central office or CO). The COs were interconnected via a second level of switching office called a toll office. Thus, the tree-like hierarchy of telephone switch offices was continued through three more levels: Primary centers, sectional centers, and regional centers respectively.
Sharing Information
Published in Kirk Hausman, Sustainable Enterprise Architecture, 2011
Voice-over-IP (VoIP) systems provide standard telephonic device communication between individuals without requiring telephony service connections or per-call long-distance fees associated with the use of a public switched telephone network (PSTN) connection. A common example of this technology is the popular Skype service, which allows telephony-style audio communication from a Skype-enabled computer or dedicated Skype phone handset.
Sensor Systems for Indoor Position Computation
Published in Krzysztof W. Kolodziej, Johan Hjelm, Local Positioning Systems, 2017
Krzysztof W. Kolodziej, Johan Hjelm
Voice-over Internet Protocol (VoIP) refers to the delivery of audio (voice) information over IP in discrete packets, rather than through the traditional circuit-committed protocols used in the public switched telephone network (PSTN). Pinpointing the exact origin of a VoIP call can be difficult to impossible using current technologies, since customers can choose distant area codes and use the service when they are away from home. There are currently a number of techniques to position VoIP calls, each with their own complications, including IP address-based location, hybrid VoIP calling (users connect to the PSTN via gateways provided by the service provider), and Dynamic Host Control Protocol (DHCP)-based positioning. Another option proposed is a DHCP-based solution (http://www.ietf.org/internet-drafts/draft-ietfgeopriv-dhcp-lci-option-03.txt). Location configuration information of varying precision is included in the protocol. The question then is one of how that location information is derived. One solution proposes smart jacks, in which the jack itself can be queried about the MAC address of devices attached (Schulzrinne and Arabshian, 2002). This would entail upgrading countless Ethernet ports with that capability. Barring that, the location of the port would have to be known and mapped. This presents a large burden to the IT manager. In contrast with network-based solutions, Rosum’s TV-GPS solution provides the absolute location of the calling device without any need for knowledge of the local wiring system and without a need to keep wiring diagrams up to date (Rosum, 2004). With Rosum TV-GPS, the device itself provides its location as a simple latitude, longitude set. In addition to map-based pinpointing like the Skyhook positioning system, Rosum TV-GPS is a mobile, handset-based solution to the VoIP geolocation problem. VoIP device locations can be kept “warm” through regular position updates, or positioned on an as-required basis. However, unlike map-based pinpointing approaches, by providing caller coordinates, Rosum’s solution eliminates the need for time-consuming updates to a centralized in-house database associating VoIP numbers with locations for the purpose of PSAP call routing. 802.11 access points would need to be mapped precisely, or the location of the Ethernet port must be known. Assigning latitude and longitude coordinates to all Wi-Fi nodes is an enormous task, as would be keeping such a database current. This approach eliminates the need to map devices to locations and enables more precise location than that offered by using the nearest router, which could be hundreds of meters away.
Design and implementation of a VoIP PBX integrated Vietnamese virtual assistant: a case study
Published in Journal of Information and Telecommunication, 2023
Hai Son Hoang, Anh Khoa Tran, Thanh Phong Doan, Huu Khoa Tran, Ngoc Minh Duc Dang, Hoang Nam Nguyen
Voice-over-Internet Protocol (VoIP) comprises a set of software and hardware technologies for making voice calls that use a data network instead of a traditional Public Switched Telephone Network (PSTN) system. VoIP is widely used in corporate environments, and the adoption of this technology by businesses is expected to continue growing in the coming years (Packer & Reuschel, 2018). The main reason for the popularity of this model is cost saving. Both large and small companies acknowledge that deploying and managing separate data and voice networks is expensive. In contrast, converged voice and data networks enable unified communications services while reducing costs. Furthermore, the costs associated with traditional phone calls are usually higher than those associated with VoIP calls (Karapantazis & Pavlidou, 2009).