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(单词翻译:双击或拖选)
I-MAC
isonchronous media access controller
IDN
integrated digital network
IEC
International Electrotechnical Commission
Impairments
Impairments is the (e.g., transmission channel and signal impairments) degradation1 caused by practical limitations of channels, (e.g., signal level loss or attenuation2, echo, various types of signal distortion, etc.) or interference induced from outside the channel (such as power-line hum or interference from heavy electrical machinery). The measurement of transmission impairments is an important aspect of predicting whether or not telecommunications systems will sustain the business applications they are intended to support. Signal-to-noise ratio, percent distortion, frequency response, and echo are measurements that define impairments most noticeable by users in analog3 voice systems.
Inbound Signaling
Inbound signaling uses not only the same channel path as the voice traffic, but the same frequency range (band) used for the voice traffic.
Independent Telephone Company (ITC)
ITC is a local exchange carrier that is not one of the 22 divested4 Bell-operating companies. ITCs are not generally subject to the restrictions5 of the MFJ, although some of the larger ones are bound by separate consent decrees. Southern New England Telephone and Cincinnati Bell are generally considered ITCs from a regulatory point of view.
Integrated Services Digital Network (ISDN)
ISDN consists of a set of standards being developed by the CCITT and various U.S. standards setting organizations. The CCITT formal recommendations, adopted in October, 1984, first defined ISDN as ". . . a network, in general evolving from a telephony integrated digital network, that provides end-to-end digital connectivity to support a wide range of services, including voice and non-voice, to which users will have access by a limited set of standard multipurpose user- network interfaces6." The concept of user access to an existing integrated digital network (IDN) underlies7 the ISDN.
Inter-LATA Services
Inter-LATA services are revenues, functions, etc., that relate to telecommunications originating in one LATA and terminating outside that LATA. An interexchange carrier (IXC) is a company which provides telecommunications services between LATAs. (the domain8 of IXCs).
Intermediate Cross Connects
In a premises9 distribution system, intermediate cross connects are cross-connects located telecommunications closets.
1 degradation | |
n.降级;低落;退化;陵削;降解;衰变 | |
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2 attenuation | |
n.变薄;弄细;稀薄化;减少 | |
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3 analog | |
n.类似物,模拟 | |
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4 divested | |
v.剥夺( divest的过去式和过去分词 );脱去(衣服);2。从…取去…;1。(给某人)脱衣服 | |
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5 restrictions | |
约束( restriction的名词复数 ); 管制; 制约因素; 带限制性的条件(或规则) | |
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6 interfaces | |
界面( interface的名词复数 ); 接口(连接两装置的电路,可使数据从一种代码转换成另一种代码); 交界; 联系 | |
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7 underlies | |
v.位于或存在于(某物)之下( underlie的第三人称单数 );构成…的基础(或起因),引起 | |
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8 domain | |
n.(活动等)领域,范围;领地,势力范围 | |
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9 premises | |
n.建筑物,房屋 | |
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