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5d80adef474749822aa4e432dd8ff22b | 101 904 | 6.6.1.1 Adjacent channel | Table 2 gives the minimum spacing between facing co-polar CRSs for quaternary modulation systems conforming to EN 301 213-1 [8] to achieve a 21 dB threshold/interference ratio assuming a 28 MHz guard band between the systems, typical for systems in the 24,5 GHz to 29,5 GHz band, assuming operation in rain zone K. Table... |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 6.6.1.2 Co-channel | In the co-channel FDD case the co-ordination distance is limited by uplink interference (i.e. a co-channel TS in a distant cell interfering with the victim CRS). The interference situation with a distant co-channel CRS is very similar, except for three distinct differences: - the interfering CRS power will be higher th... |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 6.6.2 TS - TS interference | ERC Report 99 [14] contains results of Monte-Carlo analyses of TS-TS interference. In general, the following conclusions may be drawn. ETSI ETSI TR 101 904 V1.1.1 (2001-03) 25 |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 6.6.2.1 Same area, adjacent frequency | For small values of cell overlap, where any pair of interfering TSs must be very close and the interfering TS must be transmitting at maximum power, low values of C/I can arise; made worse by rain fading. However the probability of any interference conflict arising is extremely low (of the order of 0,02 % for the scena... |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 6.6.2.2 Same frequency, adjacent area | Over the range of cell spacings of interest from the viewpoint of other interference mechanisms (principally uplink co- channel), the C/I ratio will be in excess of 50 dB for a cell boundary separation of 21 km, and the probability of interference will be ≈0,5 %. Rain fading will either improve the C/I or leave it unaf... |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 6.7 Mitigation of interference | The use of FDD-only systems, (like synchronized TDD or TDD systems one in upper and one in lower sub-band in paired spectrum) provides a useful strategy for managing CRS to CRS interference, whereas FDD does little to address the "overlapping cell issue". In this clause we shall show that there are practical ways to mi... |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 6.8 The differing views on interference scenarios | The arguments presented in clauses 6.1 to 6.6 above are drawn from several sources and they apparently show somewhat different conclusions, sometimes apparently contradictory. Whereas there is no disagreement about the existence of additional modes of interference when TDD systems coexist with FDD systems, there is lit... |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 7 Parameters for TDD systems | One objective of the present document was to identify and describe the selection of any additional parameters, or the modification of existing parameters, required for specifying the TDD characteristics of TM4 P-MP standards. This matter is addressed in the clause. |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 7.1 Classification of TDD types and synchronization issues | The main characteristics that describe the nature of TDD applied in any system are: a) the type of TDD as defined in annex B (Slotted TDD, Non slotted TDD, Random slotted TDD) according to whether the duplex time intervals are Fixed, Adaptive, Dynamic or Random allocation); b) for Slotted TDD systems only, where fixed ... |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 7.2 Suppliers' Declarations related to TDD | Some aspects of conformance testing are conducted differently for TDD and FDD systems. It is therefore necessary for the supplier to declare which duplex method is used and so the supplier is invited to declare for conformance testing the characteristics of the duplex system: a) whether TDD is used in the system; b) if... |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 7.3 Out of band aspects | It has been questioned whether different out-of-band emission characteristics (including spurious emissions) or received filter rejection characteristics should be specified for TDD systems as compared with FDD systems. One arguments advanced in clause 6 is that the carrier frequency separation to achieve the isolation... |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 7.4 System Capacity | Most existing TM4 P-MP standards specify minimum traffic capabilities by stating a minimum bit rate which can be supported by a given channel bandwidth or channel separation. This is stated in different ways in different standards. With some of the older standards this led to a potential source of confusion or ambiguit... |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 7.5 Duplex spacing | Several CEPT (and other bodies') Fixed Service channel arrangements allow for paired frequencies and often specify the separation between corresponding paired channels. Several TM4 equipment standards make explicit reference to the Tx/Rx spacing of FDD systems. Clearly, such a parameter as duplex spacing is not require... |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 7.6 Summary | Regarding the "selection, modification or addition of technical parameters relevant to the usage of TDD arrangements in FWA applications" we conclude only that only the following changes are needed to the parameters in the standards: 1) where system capacity is specified in terms other than gross bit rate then this sho... |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 8 Conclusions and proposed way ahead | |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 8.1 General conclusions | TDD has many positive attributes when applied to FWA P-MP systems (see clause 4). However, there is an understandably cautious reluctance on the part of some regulators to assign TDD systems frequencies within bands where channel arrangements permit paired radio spectrum and which have historically been used for FDD sy... |
5d80adef474749822aa4e432dd8ff22b | 101 904 | 8.2 Way ahead for TDD in TM4 P-MP standards | TM4 standards are concerned only with equipment specifications and do not define aspects of deployment, spectrum engineering and frequency management issues, which are beyond the terms of reference of ETSI, and under the purview of national regulators and international bodies such as CEPT and ITU. No exception to this ... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 2 References | The following documents contain provisions which, through reference in this text, constitute provisions of the present document. • References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. • For a specific reference, subsequent revisions do not apply. • Fo... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 3 Definitions and abbreviations | |
6480a779c035e8a15408af5eaff93820 | 101 694 | 3.1 Definitions | For the purposes of the present document, the following terms and definitions apply: AAL-5: ATM Adaptation Layer Type 5: AAL functions in support of variable bit rate, delay-tolerant connection- oriented data traffic requiring minimal sequencing or error detection support (see [8]) ATM Name Server: server program which... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 3.2 Abbreviations | For the purposes of the present document, the following abbreviations apply: AAL ATM Adaptation layer ANS ATM Name Server ARP Address Resolution Protocol ATC ATM Transfer Capability ATM Asynchronous Transfer Mode DNS Domain Name System HTTP HyperText Transfer Protocol IP Internet Protocol NHRP NBMA Next Hop Resolution ... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 4 Reference Configurations | ATM Server IP Server Gateway TE TE TE ATM Name Server ATM based Network Domain Name Server Router IP based Network TE Scenario A : Scenario B : Scenario C : Figure 1: Reference Configuration |
6480a779c035e8a15408af5eaff93820 | 101 694 | 4.1 Scenarios considered | Three scenarios are considered here: Scenario A: Between the TE and the ATM server over the ATM-based network The IP stack is not supported by the TE nor anywhere else in the ATM-based network. The transport protocol is operated directly over AAL5/ATM. IP addresses are not relevant in this scenario. Scenario B: Between... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 4.2 Functionalities | This subclause describes the functions of the various equipment involved in the provision of the service. ETSI ETSI TR 101 694 V3.0.2 (1999-09) 8 |
6480a779c035e8a15408af5eaff93820 | 101 694 | 4.2.1 Native-Mode ATM transport | The native-mode ATM transport protocol stack is used in a number of equipments. It is as follows. Internet application Transport Protocol AAL5 ATM Physical layer Figure 2: Native mode ATM transport protocol stack The transport protocol is operated directly over AAL5/ATM (an example of such a working implementation in c... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 4.2.2 ATM Network | The ATM-based network could be an ATM-based Intranet or public network using broadband access technologies. Connections within the ATM-based network are standard ATM SVCs, with standard UNI [5]. These connections can take full advantage of ATM QoS, as long as the application is able to specify the traffic parameters an... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 4.2.3 TE (Terminal Equipment) | In the following text, the abbreviation "TE" refers to the ATM-attached TE. An ATM-attached TE (Terminal Equipment) can have access to Internet applications (e.g. WEB service) provided either by an ATM server or by an IP server. The TE is able to access any ATM-based servers and interworking equipment connected to the ... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 4.2.4 ANS (ATM Name Server) | The basic service of the ANS server is the domain name to ATM address translation and reverse. The functions supported by this server are already defined by the ATM Forum [4]. The U-plane protocol stack of the ANS server is: ANS Application ATM layer Physical layer AAL5 layer Figure 3: The protocol stack of the ANS ser... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 4.2.5 ATM Server (Supporting Internet Applications) | The ATM server may fulfil the same functions as an IP server, on the level of Internet applications. In the ATM server, the Internet application (originally designed to use IP) is modified so that the primitives at the network layer act directly at the ATM level. The sequence of call of primitives remains the same. The... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 4.2.6 Gateway (between the ATM Network and the IP-based Network) | The Gateway acts as an application relay. Figure 4: The protocol stack of the Gateway, (U-plane) The IP stack is supported within the Gateway which could also include the functions of an appropriate proxy such as security and caching (see "Internet Applications over Native ATM"). |
6480a779c035e8a15408af5eaff93820 | 101 694 | 4.2.7 IP server | The IP server is a server attached to the IP network and running Internet applications. The protocol stack is as follows. Internet application TCP/UDP IP Data link layer Physical layer Figure 5: IP server protocol stack Note that the "Data link" layer is used as a generic term. When the ATM-based network is a public ne... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 4.2.8 IP Router | The IP router interfaces between the ATM network and the IP-based network. Towards the ATM network, the router is accessed for instance via Classical IP or NHRP; and towards the IP network, there is a traditional IP protocol stack. So the interworking between the networks is performed on an IP basis. Please note that t... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 5 Scenario A Description | |
6480a779c035e8a15408af5eaff93820 | 101 694 | 5.1 Terminal U-plane protocol stack | The TE protocol stack in this scenario is the Native-mode ATM transport protocol stack. |
6480a779c035e8a15408af5eaff93820 | 101 694 | 5.2 Procedures for the TE access to the ATM server | When the application refers to the destination host using the host name: - the TE sets up a connection to the ANS server; - the TE sends a query over this connection to the ANS, requesting the ATM address associated to the host name of the ATM server; - the ANS gives back a positive response to the TE with the ATM addr... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 5.3 ATM Network Related Issues | Connections within the ATM-based network can take full advantage of ATM ATC and QoS. ATC, traffic parameters and QoS are to be chosen for each ATM connection. Existing applications have no means to specify such parameters. Hence, a mechanism which could be external to the application but internal to the terminal, is re... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 5.4 Charging Issues | The charging mechanisms of the ATM switched network could be used. |
6480a779c035e8a15408af5eaff93820 | 101 694 | 6 Scenario B Description | |
6480a779c035e8a15408af5eaff93820 | 101 694 | 6.1 Terminal U-plane protocol stack | The TE protocol stack in this scenario is the Native-mode ATM transport protocol stack. |
6480a779c035e8a15408af5eaff93820 | 101 694 | 6.2 Procedures for the TE access to the IP server | - The TE sets up a connection to the ANS server; the protocol stack of the connection is the native mode ATM transport protocol stack. - The TE sends a query over this connection to the ANS, requesting the ATM address associated to the host name of the IP server. - In the case of an Intranet, where the ANS does not hav... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 6.3 Example using a web server application | In the following, the gateway is considered where HTTP protocol (HyperText Transfer Protocol) [2] and [3], operates on top of TCP [1] which is connection-oriented. In this example, TCP is running on both sides of the gateway. A HTTP request message, from a client to a server, includes within the first line of that mess... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 6.4 ATM Network Related Issues | Connections within the ATM-based network can take full advantage of ATM ATC and QoS. ATC, traffic parameters and QoS are to be chosen for each ATM connection. Existing applications have no means to specify such parameters. Hence, a mechanism which could be external to the application but internal to the terminal, is re... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 6.5 Charging Issues | The charging mechanisms of the ATM switched network could be used. ETSI ETSI TR 101 694 V3.0.2 (1999-09) 13 |
6480a779c035e8a15408af5eaff93820 | 101 694 | 7 Scenario C Description | |
6480a779c035e8a15408af5eaff93820 | 101 694 | 7.1 Terminal U-plane protocol stack | In this case, both the native ATM transport protocol stack and the IP over ATM protocol stack are supported by the TE. A pplication Transport protocol A A L5 A TM Physical layer T C P / U D P IP Figure 7: The protocol stack of the TE, (U-plane) |
6480a779c035e8a15408af5eaff93820 | 101 694 | 7.2 Procedures for the TE access to the IP server | When the TE application refers to the destination IP server using the host name, the situation is like in Scenario B. It could be envisioned that when the ANS gives back a negative response to the TE, the application takes the initiative in accessing the DNS using its IP stack, through the router. Here the decision to ... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 7.3 Example using a web server application | In the following, the gateway is considered where HTTP protocol (HyperText Transfer Protocol) [2] and [3], operates on top of TCP [1] which is connection-oriented. In this example, TCP is running on both sides of the gateway. A HTTP request message, from a client to a server, includes within the first line of that mess... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 7.4 ATM Network Related Issues | When the transport protocol is operated directly over ATM (that is when the application refers to the destination host using the host name), connections within the ATM-based network can take full advantage of ATM ATC and QoS. ATC, traffic parameters and QoS are to be chosen for each ATM connection. Existing application... |
6480a779c035e8a15408af5eaff93820 | 101 694 | 7.5 Charging Issues | When the transport protocol is operated directly over ATM (that is when the application refers to the destination host using the host name), the charging mechanisms of the ATM switched network could be used. When the application has to make use of the IP stack, the charging mechanisms described in TR 101 734 [12] could... |
af21fe75d5e50e5d8c0343df202e9a11 | 101 662-1 | 1 Scope | The present document describes scenarios whereby Internet traffic could bypass the local exchange by being routed in the Access Network directly to the Internet access services. |
af21fe75d5e50e5d8c0343df202e9a11 | 101 662-1 | 2 References | The following documents contain provisions which, through reference in this text, constitute provisions of the present document. • References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. • For a specific reference, subsequent revisions do not apply. • Fo... |
af21fe75d5e50e5d8c0343df202e9a11 | 101 662-1 | 3 Abbreviations | For the purposes of the present document, the following abbreviations apply: AN Access Network AS Access Server BCC Bearer Channel Connection CPE Customer Premises Equipment DSP Digital Signal Processor IAC Internet Access Control IP Internet Protocol ISDN Integrated Services Digital Network ISDN-BA ISDN Basic Access I... |
af21fe75d5e50e5d8c0343df202e9a11 | 101 662-1 | 4 Basic functionality of the LE Bypass mechanism | When an end customer, whose line is terminated on an AN with the Internet Bypass feature, goes off-hook, dial tone is provided by the ingress LE via the V5.2 interface just as it is done today. If the customer (or CPE) dials the destination E.164 address of a contracted ISP, the LE will re-route the Bearer channel from... |
af21fe75d5e50e5d8c0343df202e9a11 | 101 662-1 | 5 Progress of standardization work | At the outset, it was intended that the standardization should start with a simple first phase without signalling from the LE towards the AS interface. A second phase was planned for the introduction of a signalling protocol. The simple first phase was abandoned after realising that, without a signalling protocol, prop... |
af21fe75d5e50e5d8c0343df202e9a11 | 101 662-1 | 5.1 First results | The following basic requirements have been identified: • "The aim of the activity is to bypass the LE". • The V5 standard is to provide connection capabilities in the AN such that Internet traffic is directly connected from the user to the AS. • The capability should not impact on existing services; service as seen by ... |
af21fe75d5e50e5d8c0343df202e9a11 | 101 662-1 | 5.2 Open items | |
af21fe75d5e50e5d8c0343df202e9a11 | 101 662-1 | 5.2.1 General architecture | In the current V5 standard [3], the AN supports user-side to network-side connections. Signalling from the LE to the subscriber ports is passed transparently through the AN or mapped from messages to line signals. Regarding the AS interface this could be seen as a network side interface or a user port. There are advant... |
af21fe75d5e50e5d8c0343df202e9a11 | 101 662-1 | 5.2.2 AS interface | With the decoupling of Internet traffic in the AN a new interface between AN and AS is required. In the extension of the V5.2 standard for decoupling, this interface plays an important role; nevertheless it is not clear whether the interface can or should be part of the V5.2 interface or if the actual implementation of... |
af21fe75d5e50e5d8c0343df202e9a11 | 101 662-1 | 5.2.3 Signalling between LE and AS | Signalling between the AS and LE is already operational in live implementations, as the AS is connected directly to the LE, and it is essential to avoid a number of issues. Firstly, a lack of signalling implies a level of call control in the AN which is inconsistent with the existing approach in V5 and should be avoide... |
af21fe75d5e50e5d8c0343df202e9a11 | 101 662-1 | 5.3 NAS/NAS Controller architecture | As the NAS/NAS Controller architecture is quite different from the AS, the scenario warrants specific discussion. |
af21fe75d5e50e5d8c0343df202e9a11 | 101 662-1 | 5.3.1 Network architecture | The interconnection between the trunk and data networks may be achieved by using Network Access Servers (NASs) which are controlled and managed by NAS Controllers, a brief description of which is given below. LE AN AN AN NAS NAS NAS Controller Data Network Bearer Traffic Signalling Trunk Network Figure 7: Example Inter... |
af21fe75d5e50e5d8c0343df202e9a11 | 101 662-1 | 5.3.1.1 NAS Controller | The NAS Controller interfaces the LE to one or more NASs and, together with the LE, provides the call processing intelligence within the network. It is also able to exercise certain management capabilities, either automatically or on operator command. It co-ordinates the provision of services such as modem dial-up, pac... |
af21fe75d5e50e5d8c0343df202e9a11 | 101 662-1 | 5.3.1.2 Network Access Server | Under the direction of the NAS Controller, a NAS performs a number of functions involving physical components which, in general, are addressable and selectable by the NAS Controller. These functions may include the termination of modem connections, acting as a host on the packet network, and the making and breaking of ... |
af21fe75d5e50e5d8c0343df202e9a11 | 101 662-1 | 5.3.2 Internet traffic grooming within the Access Network | Internet traffic grooming within the AN allows certain traffic, under control of the LE, to use bearer channels other than those between the AN and LE. The identification of such traffic is typically based on directory numbers provisioned within the LE. For an originating call the LE will analyse the called party numbe... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 1 Scope | The present document reports the background research, symbols development and evaluation undertaken to create a European Standard on symbols to identify telecommunications facilities for the deaf and hard of hearing. The symbols defined in the final standard will be applicable to all telecommunications equipment that p... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 2 References | The following documents contain provisions which, through reference in this text, constitute provisions of the present document. • References are either specific (identified by date of publication, edition number, version number, etc.) or non-specific. • For a specific reference, subsequent revisions do not apply. • Fo... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 3 Definitions and abbreviations | |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 3.1 Definitions | For the purposes of the present document, the following terms and definitions apply: additional receiving amplification: facility provided in a terminal whereby the gain in the receiving direction from telephone line to ear may be increased (or decreased) relative to that required by the relevant terminal standard, for... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 3.2 Abbreviations | For the purposes of the present document, the following abbreviations apply: IEC International Electro-technical Committee ISO International Standards Organization |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 4 Initial Phase | The initial phase consisted of four main activities: 1. An analysis of hard of hearing and deaf people. This looks at exploring who they are and what their needs might be in relation to the use of telecommunications products and services. 2. An analysis of the telecommunications facilities that are available to assist ... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 5 Hard of hearing and Deaf People: Who are they? | |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 5.1 Introduction | Approximately 10 % of the total population has a mild to profound hearing loss. About 2 % of children under 18 have some level of hearing loss. By age 40, the incidence of hearing loss rises to 10 %. By 65, one third of the population has a hearing loss. From all people with hearing loss, 7-8 % have a profound hearing ... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 5.2 Categories of people with hearing impairment | |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 5.2.1 Hard of hearing children | There are approximately 100 deaf children, 100 severely hard of hearing children and 100 mildly hard of hearing children for each million people. In some European countries all deaf and many hard of hearing children will still be in special schools and only a few will be integrated. But for most countries a mainstreami... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 5.2.2 Adults who have been hard of hearing from childhood | Depending on the hearing loss and the time when it appeared the members of this group will have learned spoken language and be able to participate in education, vocational training and higher education according to their interests, abilities and possibilities. A very important issue will be, if they have access to all ... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 5.2.3 Deafened adults | This group can be difficult to define, it consists of those people who after they have learned the spoken language, lost their hearing to such a degree, that they can not decipher spoken language by help of their hearing even if they have the best possible hearing aids. Compared to the other groups it is a small number... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 5.2.4 People who have become hard of hearing in adult life | In the period of life where most people have a job, raise their children etc. around 10,000 per million will lose their hearing to such a degree that they will need special devices like hearing aids, amplified phones, light signals etc. to continue their existing life situation. For this group many adjustments have to ... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 5.3 Social identity of the heard of hearing | All together, some 10 % of the population in each European country and the USA have a hearing impairment. What they all have in common is that they can be characterized as having a communication disorder. They have all met problems in their daily life, where they do not have access to the same information as other citi... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 5.4 Hearing impaired, telecommunications and hearing aids | Today it is difficult to say where telecommunications begins and ends. The reason for this is that the introduction of new technology which includes digital systems, cable and radio services all interface with the basic telephone system. With these new systems and services has come the blurring of the distinctions as t... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 5.5 Discussion and conclusions | Approximately 10 % of the total population has a mild to profound hearing loss. This means that hearing loss concerns a large minority of the total population. About 2 % of children under 18 have some level of hearing loss. By 65, one third of the population has a hearing loss. This means that extra attention must be g... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6 Assistive Technologies | |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.1 Purpose | In order to assess the range of facilities for deaf and hard of hearing users that might be available now or in the future, a paper study was undertaken. From this list of facilities it was possible to determine which might those most likely to benefit from the provision of special symbols. This clause describes the ra... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2 Telephones | |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.1 General | Originally telephone terminals used carbon transmitters and moving iron receivers. The speech loudness and quality was determined largely by the efficiency of the microphone and of the receiver. Following the advent of the junction transistor it became possible to provide amplification suiTable for users with hearing i... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.2 Receiving performance | |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.2.1 General | Modern telephone terminals have a receiving performance with a sensibly flat frequency response ranging from 300 Hz to 3.4 kHz with the loudness set at a level judged to be comforTable for users with normal hearing. This level is surprisingly loud and on the majority of telephone calls in modern networks the speech lou... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.2.2 Amplification of incoming speech (additional receive gain) | When amplification of the incoming speech is intended to be of particular benefit to the hearing impaired, the gain is often so great as to require special measures to prevent instability. An ETSI Standard, ETS 300 488 [[7]], [7] specifies characteristics of telephone sets that provide additional receive amplification ... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.2.3 Provision for an additional earphone | In the past the provision of an additional earphone (sometimes known as a watch receiver) was only common in those countries where poor transmission was prevalent. Nowadays such provision is becoming more common as it has been realized that many hearing impaired users find benefit from the use of such a second earphone... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.2.4 Provision for an external headset | The use of external headsets associated with a telephone is becoming more common, either in addition to or in place of the handset. There are at present no standards for headsets or for the interface to which they are connected. Headsets are commonly used plugged into the socket intended for the handset but unless the ... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.2.5 Configurable frequency response | In the future it will be possible to configure on demand the characteristics of a Digital Signal Processor (DSP) used in a complex telephones. Such DSPs are currently only used in mobile telephones, but there is no reason apart from cost why they should not be used on other terminals such as ISDN or even PSTN telephone... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.3 Ringer | |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.3.1 General | Some form of ringer is necessary to inform the user of the presence of an incoming call. In the past the acoustic output was normally provided by a bell but nowadays a tone caller is more common. The loudness is normally limited by the availability of power from the line and the common need to connect terminals in para... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.3.2 Loud ringer | Many tone callers now have volume control provision. The volume control is more often used to reduce the loudness of the ringer. Extra loud ringers are commonly available as separate extension bells or tone callers, intended for general use to gain attention at a distance or in noisy environments and may require the pr... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.3.3 Frequency adjusTable ringer | Tone callers fitted in terminals commonly have a number of selecTable tones or tunes available that cover a range of frequencies. This can enable hearing impaired users to choose a characteristic that best compensates for their personal hearing defects. |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.3.4 Optical indication of ringing | Some terminals are provided with a lamp indication of the incoming ringing, but such indications are seldom bright enough to draw the user's attention. A range of accessories are available which function as extension ringers but which operate either a separate bright flash or a relay which can flash the domestic lighti... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.3.5 Mechanical indication of ringing | Mobile telephones and pagers are commonly fitted with vibrators (often on the battery pack) to give a discreet indication of an incoming call. Such a facility is also useful to a hearing impaired user. There is no reason why similar vibrating package should not be provided, operated by a radio signal controlled by inco... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.4 Call progress tones | |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.4.1 General | In order to set up and control the progress of a telephone call it is necessary to monitor the various call progress tones provided by the network which are needed to monitor either call set up or the various supplementary services. |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.4.2 Visual indication of tones | Hearing impaired users may have difficulty hearing the call progress tones and it is therefore necessary to provide the required information in visual form. This can be done by the use of a tone detector which either operates a lamp (or lamps) indicating the stage of call progress or which provides a text description o... |
9a43a0451fe9aaf1c9039de597a8483b | 101 767 | 6.2.5 Terminal configurable from Smartcard | In the future it can be expected that it will be possible to configure a terminal to the personal requirements of a user by means of a Smartcard. This is likely to happen in the first place with mobile telephones and later with public terminals of all kinds. As referred to in 6.2.2.2 and 6.2.2.5 above a Smartcard could... |
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