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Telephone network based on IMS technology has been widely applied inpower production and dispatching communication, especially in distributedpower stations. Analysis and positioning failure of IMS network is arduous,because it’s dependent on IP data communication network. In this paper,we first introduced IMS switching network architecture and distributed gen-eration communication network architecture, analyzed and summarized allkinds of network malfunction. Combining typical IMS network fault con-nection relations, we introduced an improved Petri net fault handling modeland reasoning method. The diagnosis and positioning results could reflectthe defects of equipment logic functions. This method on fault diagnosisand location of substation network has been proved to be effective throughpractical application.

Numerous studies have reported on the high accuracy of using voice tasks for the remote detection and monitoring of Parkinson’s Disease (PD). Most of these studies, however, report findings on a small number of voice recordings, often collected under acoustically controlled conditions, and therefore cannot scale at large without specialized equipment. In this study, we aimed to evaluate the potential of using voice as a population-based PD screening tool in resource-constrained settings. Using the standard telephone network, we processed 11,942 sustained vowel /a/ phonations from a US-English cohort comprising 1078 PD and 5453 control participants. We characterized each phonation using 304 dysphonia measures to quantify a range of vocal impairments. Given that this is a highly unbalanced problem, we used the following strategy: we selected a balanced subset (n = 3000 samples) for training and testing using 10-fold cross-validation (CV), and the remaining (unbalanced held-out dataset, n = 8942) samples for further model validation. Using robust feature selection methods we selected 27 dysphonia measures to present into a radial-basis-function support vector machine and demonstrated differentiation of PD participants from controls with 67.43% sensitivity and 67.25% specificity. These findings could help pave the way forward toward the development of an inexpensive, remote, and reliable diagnostic support tool for PD using voice as a digital biomarker.

Cloud computing is one of the leading options to store massive amount of data. The metaphor of the cloud was borrowed from old telecoms network schematics, in which the public telephone network was often represented as a cloud to denote that the just did not a matter it was just a cloud of stuff. However, cost and risk will increase inthe organization which are using cloud platforms. Hence this paper combines Cloud with blockchain technology to produce a secured file storage system. Blockchain is considered by many to be the safest technology. Here, a single file is splited and stored in blocks using the file manipulation and Advanced Encryption Standard (AES) algorithms. A high level, contract oriented language, Solidity is used for writing smart contracts. The system architecture which explains the cloud and blockchain processes is constructed. This system also ensures that it is free from attacks such as Brute force. Finally, the blockchain network in the cloud platform is implemented.

Entre 1935 y 1938-1939 la Compañía Telefónica Española construyó una central en Cáceres para instalar los equipos de la nueva red automática de telefonía. Fue diseñada por Paulino Justo Gayo Marín, arquitecto que tuvo gran protagonismo en el desarrollo de este tipo de arquitectura en España. Las centrales telefónicas fueron edificios diseñados con una doble intención: incorporar modernos sistemas de comunicación y proyec-tar edificios con una estética «propagandística», cuya finalidad era atraer a inversores y accionistas. Este ar-tículo trata de explicar tras un pequeño recorrido histórico y arquitectónico, la creación y las ideas constructi-vas de la compañía española, para conocer el valor que tiene la obra de Cáceres en el desarrollo urbano de la ciudad.

Latest technologies of voice over IP (VoIP) and mobile messaging for smartphones messengers such as WhatsApp, Viber, Skype, etc., offer free-of-charge facilities of worldwide SMS, MMS, and voice calls to their users, unlike the traditional and expensive cellular or telephone networks’ services. Customers of the formerly mentioned messengers are estimated in millions because of the attractive features offered by them. However, these messengers face many cyber security threats and the required security features are either not available at all or are insufficient for efficiently countering the threats. Professionals working in the domain of cyber security are challenged by the devastating effects of distributed denial of service (DDoS) attacks on all major platforms including Apple Macintosh, Windows, Unix, and Linux. In this paper, we demonstrate the effect of DDoS attack on the performance of an IRC server using a test bed. We use a game theoretic model to analyze the feasibility of DDoS attacks on the IRC platform, keeping in view the attacker’s objective. The analysis will help the security experts to propose appropriate countermeasures to reduce the attackers’ utility, thereby making it less attractive for those attackers to launch the attack.

The ideas of q-rung ortho pair fuzzy set (q-ROPFS) and interval-valued q-rung ortho pair fuzzy set (IVq-ROPFS) are two major recent developments in the field of fuzzy set theory. A q-ROPFS and IVq-ROPFS improved the limited structures of Pythagorean fuzzy set, intuitionistic fuzzy set as well as fuzzy set by improving the conditions that makes these concepts restricted. The goal of this research is to introduce a new notion of interval-valued q-rung ortho pair fuzzy graph (IVQ-ROPFG) and to study the related graphical terms such as subgraph, complement, degree of vertices and path etc. Each of the graphical concept is demonstrated with an example. Another valuable contribution of this manuscript is the modeling of some traffic networks, telephone networks and social networks using the concepts of IVQ-ROPFGs. First, the famous problem of finding a shortest path in a traffic network is studied using two different approaches. A study of social network describing the strength of co-authorship between different researchers from several countries is also established using the concept of IVq-ROPFGs. Finally, a telephone networking problem is demonstrated showing the calling ratios of incoming and outgoing calls among a group of people. Two engineering decision-making problems are also studied using some aggregation operators and the concepts of IVq-ROPFGs. Through comparative study, the advantages of working in the environment of IVq-ROPFG are specified.

Multistage interconnection networks are used as a medium for interconnecting processors and memories in multiprocessor systems. Multistage interconnection networks are an effective substitute for crossbar switches, used in telephone network systems and parallel computers, due to their low cost, better performance and easy maintainability. In this paper, we propose new fault-tolerant hybrid multistage interconnection networks obtained from shuffle exchange gamma interconnection network (SEGIN) and logical neighborhood network named as shuffle exchange gamma logical neighborhood interconnection network (SEGLNIN). We evaluated the performance of SEGLNIN in terms of disjoint paths, reliability and hardware cost and compared it with some well-known MINs like shuffle exchange network (SEN), shuffle exchange network with one extra stage (SEN +) and shuffle exchange network with two extra stages (SEN + 2), SEGIN-1, and SEGIN-2. The results illustrate that the performance of the proposed SEGLNIN is better than that of the compared networks in terms of reliability and disjoint paths.

This article analyzes how software pirates who formed the ‘warez scene’ appropriated telephone network infrastructures and Bulletin Board System (or BBS) technology to circulate computer so...

This paper introduces the concept of Phone of Things (PoT), a novel approach to extend the connectivity options for IoT systems through the pervasive telephone network infrastructure. This is a paradigm shift that integrates traditional telephones to monitor and control IoT-enabled devices via VoIP protocols and public switched telephone network (PSTN). This integration democratizes IoT through the promotion of a Do-It-Yourself (DIY) IoT system that takes advantage of the freedom the comes with open-source technologies and leverages the emerging cloud-hosted services to build customized IoT solutions while accentuating affordability, accessibility, performance, ease of use, and security. Nevertheless, the proposed system inhibits a modular design philosophy that allows the system to be tailored and scaled according to the application needs with minimum hardware and software modification requirements. The proposed paradigm provides an arbitrarily shared data space between IoT systems which would coalesce into a social network of things (SNT) and support assistive services in public sensing.

Malicious phone calls, including spam and scams, caused millions of global financial losses every year and was a difficult problem over many years. This work introduces the solution based on machine learning for telecommunications without underlying the telephone network infrastructure. The major obstacle of this ten years old problem is building efficient functions without access to the telephony network infrastructures. The previous Spam Call data set is collected first. The dataset includes several labelbased features to predict malicious calling. We primarily focus on using Recurrent Neural Network (RNN) algorithm to detect the malicious calls. With the proposed features, we review different state of the art methods of machine-learning, and it is inferred that the most optimal approach can minimize malicious calls to 90% while keeping over 90% of the binary call accuracy. The outcomes also show that without significant overhead latency the models can be implemented effectively with the help of an evaluation analysis.

Many articles have used voice analysis to detect Parkinson's disease (PD), but few have focused on the early stages of the disease and the gender effect. In this article, we have adapted the latest speaker recognition system, called x-vectors, in order to detect an early stage of PD from voice analysis. X-vectors are embeddings extracted from a deep neural network, which provide robust speaker representations and improve speaker recognition when large amounts of training data are used. Our goal was to assess whether, in the context of early PD detection, this technique would outperform the more standard classifier MFCC-GMM (Mel-Frequency Cepstral Coefficients - Gaussian Mixture Model) and, if so, under which conditions. We recorded 221 French speakers (including recently diagnosed PD subjects and healthy controls) with a high-quality microphone and with their own telephone. Men and women were analyzed separately in order to have more precise models and to assess a possible gender effect. Several experimental and methodological aspects were tested in order to analyze their impacts on classification performance. We assessed the impact of audio segment duration, data augmentation, type of dataset used for the neural network training, kind of speech tasks, and back-end analyses. X-vectors technique provided better classification performances than MFCC-GMM for text-independent tasks, and seemed to be particularly suited for the early detection of PD in women (7 to 15% improvement). This result was observed for both recording types (high-quality microphone and telephone)., Submitted

The term “SDN” represents a significant evolution in networking technology and draws attention and support from network operators, vendors, researchers and industry regulators. Contrary to popular belief that SDN is a recent invention, or is related only to IP technologies, the concept of network programmability and control/data plane separation has its roots in the 1960s and 1970s when the telephone network started its transition to digital. Many iterations followed, leading to applications in packet networks and today’s Internet. In this article, we review a number of early works on network programmability that illustrate how several features of SDN emerged progressively over several decades. Our review starts from the early concepts of network control in the telephone network and continues to examine a prolific period of research advancements in the 1990s and early 2000s that led to a number of startup companies that followed, IEEE’s own efforts in standardizing network programmability, and finally the arrival of the OpenFlow standard. We study the importance of this architectural transformation and its influences on modern cloud computing and next-generation networking.

Before focusing our interest on telecommunication networks, it is important to take a brief look at the history of telecommunications, referring to the most important steps, which are at the basis of modern transmissions of signals at distance.

Telephones are one of the most common telecommunication devices in the protected premises. The telephone includes various acoustic transducers (speaker, microphone), as a result of which these devices have a microphone effect and can cause leakage of speech information into the telephone network. This paper describes the model of the piezoelectric speaker of the Gigaset DA210 telephone connected to the buzzer circuit using simulations in COMSOL Multiphysics. The piezoelectric (Lead Zirconate Titanate 8) actuator is investigated, a comparison based on the obtained results of acoustic transducers is made with the parameters specified by the piezoelectric speaker designers. The paper studies the characteristics of this piezoelectric speaker as a sensor under the influence of an acoustic field, as a result of which a technical channel of speech information leakage channel. Based on the data obtained, the speech intelligibility assessment in the telephone network is made using the developed model. The results can be used in the development of secure telephones and the educational process in the training of specialists in the area of information security.

The 5G network phasing system is a remote phasing system that uses 5G network timing technology, wireless transmission technology, telephone network, ultrahigh voltage spark discharge processing, and phasing recognition to be applied to power systems. It can achieve ultra-high voltage and remote phasing in a few seconds. Measurement of distance, phase difference between power systems in different places, determination of phase, and calculation of phase angle. This system is mainly composed of server (platform layer) base station group (sensing layer), handheld terminal (sensing layer and application layer) and network layer (LAN/WIFI/5G network or electric power network). After testing, the system has been successfully applied in the power supply company's operation, maintenance, and technological transformation projects, and the application situation is explained in detail.

E-commerce conceivable future trade, consumption, and service is a new digital employer mode. Therefore, in order to decorate the customary natural environment of operation, it is quintessential to get rid of the preferred desktop in the true field, create a social logistics and transportation administration computing device with commodity agents and distributors as the key features, and mix freight logistics, business enterprise approach waft and data waft advertising and marketing, and advertising and marketing organically. The notion of e-commerce logistics looks alongside the enchantment vogue of neighborhood technological knowledge and social demand. It is an integral part of ending e-commerce authentic economic value. All kinds of cell networks clear up the problem of data flow communication; in the technological know-how of telephone network, digital cost solves the bother of capital flow; at present, logistics is however a long-standing problem of e-commerce. Logistics has grown to be the last and entirely bottleneck of e-commerce. If logistics cannot adapt to the enchantment of e-commerce, it may also additionally lead to the slow enchantment of e-commerce. The purpose of this paper is to supply an Internet of things (IoT) e-commerce logistics cloud provider platform based totally absolutely on cell communication, which can be combined with e-commerce and beautify the transport tempo of e-commerce. This paper moreover optimizes the e-commerce logistics system, so that it can combine with e-commerce to increase out the distribution of goods, the distribution tempo of e-commerce is doubled, and e-commerce can in a similar fashion develop rapidly.

The robocall epidemic has caused millions of phone scam victims resulting in billions of financial loss in the USA. To address this issue, Federal Communication Commission (FCC) mandates all Internet Telephony Service Providers (ITSP) to implement Secure Telephony Identity Revisited (STIR) with the Signature-based Handling of Asserted information using toKENs (SHAKEN) to authenticate Voice of Internet Protocol (VoIP) calls on their networks. This chapter provides an analysis of the effectiveness of STIR/SHAKEN in protecting users from being victims of robocalls which are mostly scam calls with fake caller ID. Our analysis shows three majors issues that could have impact on the effectiveness of STIR/SHAKEN. These issues are (a) poorly protected enterprise IP-PBX, (b) unscrupulous service providers, and (c) lack of support of Q.1912.5, which is the interworking standard between IP and Public Switch Telephone Network (PSTN).

Being part of the so-called “Pacific Ring of Fire” and “Belt of Low Pressure,” Ecuador is located in one area most likely to suffer seismic, volcanic, and hydrometeorological threats, which make it possible to catalog as a country with a high vulnerability. For this reason, the use of alert systems such as Emergency Warning Broadcasting System EWBS is necessary for the face of one of these threats, which can be implemented in analog and digital broadcast signals such as Digital Terrestrial Television. In an emergency, the receivers compatible with the EWBS are currently the decoders or digital televisions that include this system. They turn on automatically and emit a visual and audible alert signal that gives time to the population to act more quickly to an event. This article presents the design proposal of a receiver that replicates the warning emergency alert EWBS for digital terrestrial television with the ISDB-Tb standard, through an institutional telephone PBX, implementing an IP telephony server that receives the EWBS system and replicates it to landlines, infocast systems, and mobile phones connected to it, thus avoiding a percentage of losses in the economic and human fields.

The division of a frequency band into dedicated channels by modulation, called frequency-division multiplexing (FDM), has a long history. Prominent examples are the analog telephone networks until the 1970s. They were replaced by digital telephony, operating with time-division multiplex (TDM), in which dedicated time slot are allocated to each application. Moreover, the analog and later the digital television broadcasting networks—terrestrial, satellite and cable based—operate with FDM. Most mobile and cellular networks today utilize combinations of FDM and TDM.

Telephone operation, one of the most common jobs for young American women in the early 1900s, provided hundreds of thousands of female workers a pathway into the labor force. Between 1920 and 1940, AT&T adopted mechanical switching technology in more than half of the U.S. telephone network, replacing manual operation. We show that although automation eliminated most of these jobs, it did not affect future cohorts' overall employment: the decline in demand for operators was counteracted by growth in both middle-skill jobs like secretarial work and lower-skill service jobs, which absorbed future generations. Using a new genealogy-based census linking method, we show that incumbent telephone operators were most impacted by automation, and a decade later were more likely to be in lower-paying occupations or have left the labor force entirely.

Encryption plays a major role in achieving privacy, especially in communications and information systems such as military systems, banks, telecommunications and individuals, and in mobile phone networks in particular. The (GSM) standard provides a level of privacy that may not be sufficient for some users, as this study is presented a proposed system for applying audio coding in cellular communication networks from the beginning (mobile) to the end (mobile (via the standard mobile communications system) GSM), and in this standard is used the A5 algorithm for audio coding is only for transmitting stations, while for the rest of the network it is without transmitting coding the data as it is, so we in this study proposed the application of RC4 algorithm with A5 algorithm through encryption keys controlled by the sender and receiver in audio coding from start to finish to ensure complete encryption and privacy in network phone calls and the tool used in this the research is a matlab program to create a simulated environment for the transmission between the sender and the receiver to add the RC4 algorithm for these stages and one of the results of the study using the RC4 algorithm in the transmission model in the telephone network can achieve greater privacy in telephone calls communication without affecting the sound quality through the two encryption keys controlled by both ends connection.

This paper presents a review of the history of the insular telephone network of Tenerife (RTIT). The development of this telephone service was the best example in the Canary Islands of the commitment of a local administration, as its implementation represented a great economic effort at a time when the economy of the archipelago had not yet recovered from the crisis of the Great War. With this, it was possible to create a communication ring that managed to connect almost all the inhabited nuclei on the island, which continued even beyond the concession of the telephone monopoly in Spain to the CTNE in 1924., En este trabajo se analiza, por primera vez, la trayectoria histórica de la Red Telefónica Insular de Tenerife (RTIT), que constituyó el mejor ejemplo en Canarias de compromiso de la administración local con el desarrollo del servicio telefónico desde una perspectiva social, y su tendido supuso un gran esfuerzo económico en una etapa en que la economía del Archipiélago aún no se había recuperado de la crisis de la Gran Guerra. De este modo se consiguió crear un anillo de comunicaciones que consiguió conectar prácticamente todos los núcleos habitados de la isla, y que tuvo permanencia incluso más allá de la concesión del monopolio de servicio a la Compañía Telefónica Nacional de España (CTNE) en 1924.

On dokuzuncu yüzyılın bilim ve teknik alanındaki başlıca icatlarından biri telefondur. 1875’teki icadından sonra dünya ülkelerine hızla yayılmıştır. Osmanlılar, patenti Alexander Graham Bell tarafından 1876’de alınan telefon ile II. Abdülhamid döneminde, 1881’de tanışmıştır. Ancak telefonla ilk deneyimleri çok kısa sürmüştür: Telefon, “gizli-saklı” işlerde kullanılma ihtimali üzerine, 1886’da yasaklanmıştır. Avrupa’dan Osmanlı liman kentlerine gelen telefonlar gümrüklerde “tevkif edilerek” muhafaza altına alınmıştır. Bu tedbirlere rağmen telefonun kaçak yollarla ülkeye girişi engellenememiş ve zaman içerisinde kullanımına yönelik talepler artmıştır. II. Meşrutiyet’in liberal politikaları çerçevesinde yabancı şirketlere imtiyaz verilerek telefon kullanımı teşvik edilmiştir. İstanbul, telefon ile özdeşleşen başlıca Osmanlı kenti olmuştur. İzmir ve Aydın gibi ticaret kentleri ile Anadolu’nun muhtelif yerlerindeki kullanımı sınırlı kalmıştır. Telefonun Osmanlı’ya ilk girişinden serbest bırakılmasına kadar geçen sürede, popüler süreli yayınlarda telefona dair geniş bir literatür oluşmuştur. Bu süre içerisinde, telefon kullanımı konusunda gelişmiş ülkelere nazaran oldukça geri kalan Osmanlı’nın telefonla imtihanı yoğun bürokratik yazışmalarda da kendini göstermiştir. An important technological advance of the nineteenth century, the telephone, spread throughout the world following its invention in 1875. Patented by Alexander Graham Bell in 1876, it was introduced in the Ottoman Empire in 1881 during Abdulhamid II’s reign. The Ottomans’ experience with the device was rather short: It was prohibited because of possible clandestine uses. Devices arriving in Ottoman harbours were seized and stored. However, the illegal import of the telephones could not be prevented because of increasing demands. The liberalistic policies of the Second Constitution that extended privileges to foreign companies, encouraged its use. Istanbul had the largest telephone network but its use was limited in İzmir, Aydın and other Anatolian cities. From its introduction to its free use in 1908, a large amount of literature appeared in popular periodicals. Telephone-related issues were discussed in many bureaucratic documents which witnessed its delayed adoption in the Empire, compared to developed countries of the time.

Voice over Internet Protocol (VoIP) is a technology that allows people to use the Internet, rather than a traditional telephone network. VoIP is becoming more and more popular due to its significant advantages. VoIP telephony has become the most developed and frequently used cellular service. It also created new threats to caller’s privacy. Due to the high degree of interest in ensuring anonymization of calls in the GSM network. Previous research on the development of algorithms to increase anonymization in IP-telephony and their implementation. In this work, we developed a new mechanism for achieving anonymity in the Global System for Mobile Communications (GSM - Global System for Mobile Communications). The lowest probability of anonymity disclosure in this algorithm is achieved by redirecting calls from one mobile operator to another. In addition, GPSS-Studio implements a model for redirecting incoming calls using multi-channel modeling. Probabilistic-temporal characteristics of the distribution of incoming calls to specific nodes.

Розвиток Інтернет технологій характеризується широкими можливостями впровадження різноманітних телекомунікаційних послуг, зокрема IP-телефонії, що надає користувачам нову технологію передачі мультимедійного трафіку з використанням Інтернет мереж. Для застосування цієї технології активно проваджуються спеціальні протоколи передачі даних – SIP та H.323, що надає можливість організовувати приватні та корпоративні мережі передачі даних. У статті проведений аналіз застосування даних протоколів на базі IP-станції Panasonic KX-NS500, що дало змогу надати рекомендації щодо підвищення ефективності функціонування внутрішньої телефонної мережі для передачі голосового трафіку при різних типах кодеків. Авторами розглядається задача підвищення ефективності функціонування мережі голосового зв’язку на базі IP-станції із застосуванням протоколів SIP та H.323. Запропоновано модель зв’язку, у якій використовуються три аналогові телефонні апарати та три IPтелефони, обслуговуванням яких займається ІР-станція. Телефонна лінія використовує протокол SIP. Для дослідження характеристик роботи запропонованої моделі мережі використовується програмне середовище OPNET Modeler. Визначено оптимальний тип голосового кодеку для протоколу SIP та можливості використання застосовуваного протоколу в організації внутрішньої телефонної мережі з використанням IP-станції. Проведено моделювання сегменту телекомунікаційної мережі із застосуванням протоколу SIP та проведено аналіз характеристик двох кодеків зв’язку, що найчастіше використовуються у технології VoIP. На основі проведеного моделювання здійснено оцінку якості мовного сигналу за рейтингом MOS, діапазону затримки мовного сигналу та вибір кодеку для відтворення голосового сигналу для запропонованої моделі мережі. The development of Internet technologies is characterized by wide possibilities for introducing various telecommunication services, in particular IP telephony, which provides users with a new technology for multimedia traffic transmittion using Internet networks. Special data transfer protocols (SIP and H.323) are being actively developed to apply this technology, which enables the organization of private and corporate data networks. The paper analyzes the use of these protocols based on the Panasonic KX-NS500 IP station, which has made it possible to give recommendations on improving the operation of internal telephone network for the transmission of voice traffic for various types of codecs. The article discusses the problem of improving the efficiency of IP based voice communications using SIP and H.323 protocols. A communication model, that uses three analog phones and three IP phones serviced by an IP station, is proposed. The telephone line uses SIP protocol. The OPNET Modeler software environment is used to investigate the performance of the proposed network model. The optimal type of voice codec for SIP protocol and the possibilities of using the protocol in the organization of internal telephone network using the IP station are determined. The telecommunication network segment using SIP protocol has been simulated and the characteristics of two communication codecs most commonly used in VoIP technology have been analyzed. Based on the simulation, the assessment of the quality of the speech signal by the MOS rating, the range of delay of the speech signal and the choice of a codec to play a voice signal for the proposed network model have been made

On the basis of the economic theory of network effects, this article provides a novel explanation of the so-called patent paradox, i.e. the question why the propensity to patent is so strong when the expected average value of most patents is low. It demonstrates that the patent system of a country resembles a telephone network or a social media platform. Patents are perceived as nodes in a virtual network that, as a whole, exhibits network effects. It is explained why patents are not independent of other patents but that they complement each other in several ways both within and beyond markets and fields of technology, and that patents thus create synchronization value over and above individual interests of patent holders in exclusivity. As a consequence, the more patents there are, the more valuable it is to also seek patents, and vice versa. Since patents thus display increasing returns to adoption, the willingness to pay for the next patent slopes upwards. This explains why, after a phase of early instability and a certain tipping point, many countries’ patent systems expanded quickly and eventually became a rigid standard (“lock-in”). The concluding section raises the question what regulatory measures are suitable to effectively address the ensuing anticommons effects.

Classic public switched telephone networks (PSTN) are often a black box for VoIP network providers, as they have no access to performance indicators, such as delay or packet loss. Only the degraded output speech signal can be used to monitor the speech quality of these networks. However, the current state-of-the-art speech quality models are not reliable enough to be used for live monitoring. One of the reasons for this is that PSTN distortions can be unique depending on the provider and country, which makes it difficult to train a model that generalizes well for different PSTN networks. In this paper, we present a new open-source PSTN speech quality test set with over 1000 crowdsourced real phone calls. Our proposed no-reference model outperforms the full-reference POLQA and no-reference P.563 on the validation and test set. Further, we analyzed the influence of file cropping on the perceived speech quality and the influence of the number of ratings and training size on the model accuracy.

While the experienced quality of a conversation transmitted over a telephone network is dependent on the parameters of the network and possible degradations, it has been shown that the sensitivity to these degradations is influenced by the type of the conversation and its contents. Especially for delayed speech transmission the conversational scenario and the adaption of turn-taking behavior of the interlocutors factor into the conversational quality rating of a specific conversation. Parametric Conversation Analysis has been proven to be a good method to extract parameters from a recorded conversation that are representable of the interactivity. While the narrowband version of a popular and standardized quality prediction model, the E-model, uses the interactivity to predict a conversational quality MOS for the given conditions, there are no attempts to predict the conversational quality of individual conversations so far. In this paper, we propose a model to predict the quality of a conversation under the influence of transmission delay based on the interactivity parameters extracted from that conversation. We evaluate which parameters are most suited for such a prediction, and compare our results to the parameter-based predictions of the E-model.

Tema članka je razvoj javne nepokretne i pokretne telefonije u Hrvatskoj pod okriljem novoosnovane nacionalne javne poštansko-telekomunikacijske tvrtke Hrvatska pošta i telekomunikacije od 1990. pa sve do njezina razdruživanja na dvije zasebne tvrtke: Hrvatska pošta d.d. i Hrvatske telekomunikacije d.d. početkom 1999. godine. Hrvatska je u razvoju javne telefonske mreže znatno zaostajala za razvijenim europskim zemljama, a izbijanje Domovinskoga rata i oružana agresija na Republiku Hrvatsku izložili su ju mogućnosti telekomunikacijske i informacijske blokade. Budući da su se građani Hrvatske opredijelili za tržišnu ekonomiju, politički pluralizam i demokratsko društveno uređenje, u načelu se podrazumijevala i poticala sloboda neposrednoga komuniciranja, a ona je, telekomunikacijski gledano, na razini pojedinca ponajviše bila izražena u dostupnosti domaćih i međunarodnih javnih telefonskih veza. U obrađenom su razdoblju na nacionalnom planu napravljeni ključni infrastrukturni zahvati i uvedena je suvremena tehnologija s novim telekomunikacijskim uslugama, što je omogućilo da Hrvatska prestane biti telekomunikacijski nerazvijena, a na međunarodnom planu postala je prepoznatljiv telekomunikacijski partner te dio tranzitnoga telekomunikacijskog mosta između istočne i zapadne te sjeverne i južne Europe., After the independence of the Republic of Croatia was declared in 1991, the newly-formed national postal and telecommunications company HPT (Croatian Post and Telecommunications) found itself in an unenviable position. Croatia was in the group of countries at the forefront of telecommunications development in Europe. In 1990, it had only 17 telephone connections per 100 inhabitants. However, in the next eight years it moved closer to the European average, doubling its capacity to 35 telephone lines per 100 inhabitants by 1999. It did so despite the devastation of the Homeland War and the enormous damage suffered by its public telephone network. Croatia managed to negate the telecommunications blockade by finding alternative telecommunication routes, and then set out to build an efficient telephony and transmission system based on the use of fibre-optic cables and modern switching equipment. By the end of 1993, international switching hubs in Zagreb, Split, Rijeka, and Đakovo using AXE 10 technology were built, and the following year cities on the Croatian Adriatic coast were connected with cities in continental Croatia by fibre-optic cable. During this process, Croatia received its one-millionth telephone subscriber. Thanks to its participation in the TEL (Trans Europe Line) project, it became part of the telecommunication bridge between Eastern and Western Europe. In addition to the fixed public telephone network, it simultaneously developed a mobile public telephone network, first an analogue mobile network aptly named MOBITEL in 1991, and then the CRONET digital mobile network in 1996. These steps resulted in a significant increase in telephone traffic and the widespread availability of fixed and mobile telephone connections, which completely revolutionised public telephony in Croatia.

One of the most frequently encountered auxiliary technical devices installed in a protected room is a telephone that created acoustoelectric leakage channels of the acoustic speech information. In the NI Multisim simulation environment, typical models of passive telephone protection devices have been designed. The device protects a telephone set of the speech information leakage arising from the acoustoelectric effect and «high-frequency injection». The study was carried out of the main characteristics of the developed protection device and an assessment of the performance when connected to a telephone network using the virtual laboratory bench.