Glossaries

• Erbium Doped Fiber Amplifier (EDFA)
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• Error Free Second (EFS)
• In T1 and E1 systems, a second where no error blocks are received.
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• Electro-Magnetic Compatibility (EMC)
• The field of electrical sciences that addresses a device's unintended electro-magnetic radiation or its vulnerability to spare radiation in order to prevent interference.
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• Electro-Magnetic Interference (EMI)
• Interference from an external source that disturbs an electrical circuit and prevents it from operating normally.
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• Embedded Operations Channel (EOC)
• A channel in a telecommunication facility provided specifically for administration, operations, and maintenance.
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• Errored Second (ES)
• An interval of a second during which any possible error has occurred.
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• Extended Super Frame (ESF)
• In T1 circuits this consists of 24 frames of 192 bits each, with the 193rd bit for timing and CRC check.
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• Errored Second Ratio (ESR)
• The ratio of errored seconds (ES) to total number of seconds during any given measurement interval.
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• Ethernet Synchronization Messaging Channel (ESMC)
• Ethernet Synchronization Messaging Channel (ESMC) for Synchronous Ethernet links are communication channels where Synchronization Status Messages (SSM) are exchanged. The ESMC protocol is composed of the standard Ethernet header for a slow protocol, an ITU-T specific header, a flag field and a type length value (TLV) structure.
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• European Telecommunication (ETSI)
• Standards making organization in Europe. Similar to ANSI and CSA, but specifically for the telecom industry.
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• External Clock (EXT CLK)
• A timing signal external to the operating unit, to which the unit is synchronized.
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