• ETRI Journal
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• v.10 no.2
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• pp.13-19
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• 1988

This paper describes on the interworking services. interworking issues and the design concepts in the Interworking System (IWS) between Pubilc Switched Telephone Network (PSTN) and Packet Switched Data Network (PSDN), which has been developed at the Electronics and Tedecommunications Research Institute (ETRI). As a gateway between PSTN and PSDN, IWS provides the interconnection between PSTN and PSDN. In addition to the provision of basic interconnection services (i.e. dial-in/dial-out services), IWS provides the Maintenance and Administration (M&A) services for system itself and the supplementary services such as the call barring, direct call and closed user group. The architecture of IWS is based on the multiprocessor system with single system bus. And a multiprocessor real time kernel is used to support the inter-board communication as well as the inter-process commmunications. Especially, the operation and maintenance functions of IWS are treated in detail.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.10C
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• pp.921-932
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• 2002

In this research, we seek to identify an effective operation management strategy of telecommunication systems. In order to develop operation management strategies, we implement a quantitative techno-economic analysis. We evaluate related issues and factors, and apply the developed method to PSTN switching systems. In the proposed techno-economic modeling, we apply a well-known factor analysis technique-analytic hierarchy process-to evaluate PSTN operation management strategies. Then, we implement a decision analysis methodology to evaluate the cost of proposed strategies. We evaluate the proposed methodology by using available real data of the PSTN system. The primary impact of this research will be realized in helping PSTN operator select the best operation management strategy of PSTN system.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.5
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• pp.28-35
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• 2000

In this paper, we design a ring inductor using the ferrite core to denoise the EMI(Electromagnetic Interference) for facsimile. The EMI for facsimile is radiated from the signal line of PSTN(Public Switching Telephone Network) between facsimile and PSTN. We denoise the radiated noise by inserting a ferrite core(Ni-Zn) between facsimile and PSTN. Even though we may denoise the radiated noise using two or more than two ferrite cores, we only concentrate on denoising EMI by adjusting number of turns of one ferrite core since it gives economical gain. As a result of measuring EMI using the designed inductor with 4 turns inserted in the line connected between facsimile and PSTN, the value of radiated emission is reduced below 30 dB$\mu$V/m.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8357-8362
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• 2015

The emergency call device has been installed and operated for the elevator passenger safety, but the call can not be connected or delay to the operator in an emergency. The application of the Internet of Things(IoT) technology is required for the systematic management and reliability of the emergency call device installed in the elevator. To meet these requirements it is necessary to apply the RMS(Remote Management System). Emergency call device periodically reports the operating status information and the emergency call history information of the emergency call device to the RMS in the PSTN(Public Switched Telephone Network) environment, and transmits the call request information in an emergency. RAS(Remote Access Server) plays a role of converting the PSTN signals to TCP / IP. RMS reports a significant outbreak call and abnormal operating conditions to administrators. In this study, we developed optimized protocol to PSTN environment that is required by RMS and implemented its differentiated process. And a RAS-RMS Protocol was added to the Application Layer. Development protocol consisting of simple structure as compared to CoAP, MQTT or HTTP can work properly in low-spec CPU and transmit elevator emergency key information easily.

• The KIPS Transactions:PartC
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• v.15C no.5
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• pp.367-374
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• 2008

To realize the voice privacy between CDMA mobile phone and PSTN terminal, the voice frames shall be transmitted transparently between the heterogeneous networks. For satisfying this requirement, we propose the method which transmits voice frames using the CDMA circuit data channel in real time. In this paper we analyze the causes of voice delay which occurs during voice transmission using circuit data channel. And in order to overcome this kind of delay, the technique controlling the TCP control flag and the variable audio block construction algorithm according to the vocoder output rate are proposed. As a result of experimenting by applying the proposed method, we confirmed that the transit delay was improved with about average 70%.

• Information and Communications Magazine
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• v.11 no.2
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• pp.113-122
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• 1994

In this paper, We analyze and inspect the problem of our country PSTN subscriber telephone number and suggest the ISDN/PSTN subsciber numbering plan in the future. Expecially, when you eastablish plan to change present telephone number system to ISDN telephone number system, public goverment and public office which has many calls have to be given a same number that many people want and being easy rememberance thoughout the country. Therefore we think that it is saving hours and reduce lost calls. As concrete action of convert plan it must be made consistent numbering plan when the numbering reorganization is carried out in Korea before T-time. If a partial is not carried out, it should be given when the telephone number is newly-organized or the big buliding and goverment and public office eastablich RSS individually. At that time chaos will be minimized.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.600-603
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• 2007

미래 지식정보사회는 컴퓨터, 통신, 방송 등 모든 정보통신 기기가 하나의 네트워크에 연결되는 BcN 기반의 네트워크사회(Broadband Network Society)로 빠르게 진화할 전망이다. BeN은 엑세스망, IP전달망, 제어/서비스망(교환망 IP전환)의 3개 계층을 모두 포함하는 개념이나 엑세스망, IP전달망은 기존과 통일한 IP방식으로 추진 중이어서 IP기반의 제어/서비스망 신규 구축 및 교환망의 IP로의 전환을 협의의 BcN이라 정의 한다. PSTN에서 BcN망으로 전환 시 BeN망의 구성 요소는 소프트스위치, TGW, AGW, SGW, 응용서버, 미디어서버 등이 있다. PSTN망이 BcN망으로 전환시 크게 3단계의 과정을 거친다. 1단계로 2007년 상반기에 전남 목포지역의 지능망 서비스가 불가한 시외교환기가 BcN으로 전환되었다. 전환 후의 IP망을 경유하는 음성호의 트래픽을 측정한 결과는 발생호는 증가하였으며 완료율은0.06% 감소하였지만 관리 기준내의 양호한 수준이었다. 향후 음성호의 통화 품질을 높이기 위해서 품질 측정을 통한 기준 미달 항목을 조치하고 트래픽 측정을 통한 소통율, 완료율 불량 구간에 대한 지속적인 개선 활동을 해야 한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.83-89
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• 2011

Nowadays, Internet Telephony Services based on SIP are gaining an explosive increase for general user. Thus a various demands of the user about convenience of IP-PBX are growing. The most important requirements of these is hybrid IP telephony system which is connected not only internet telephone but also general PSTN telephone. Therefore, in this paper, we have developed Hybrid IP-PBX connected all type of telephony terminals for small office. We have developed FXS module for connecting all type and FXO for using PSTN telephone number also. This Hybrid IP-PBX that is can be connected Soft-phone provide various optional services. We measured voice quality and test simultaneous calling for proof of validity.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.911-915
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• 1987

In this thesis, the architecture and design of IWS(Inter Working System) which interconnects two different networks (PSDN: Packet Switched Data Network, PSTN:Public Switched Telephone Network) are described. IWS provides interconnection services for the compatibility of communication between two networks. IWS consists of network interface protocols, protocol conversion facilities and management facilities.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11
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• pp.3060-3069
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• 1999

The existed transmissions have PDH and SDH transmission system, which are based on PSTN network. But as the future ATM network is going to be constructed, it is very necessary for ATM network to interwork with PSTN for telephony service. The international standardization organizations like ITU-T, ATM Forum offered CES, VTOA1, VTOA2 and so on for interworking with PSTN service, which spend many network resources and considerable transmission delay. So in this paper, new interworking PSTN for transmission will be proposed to lessen the transmission delay and the network resources.