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- Recommendation K.23
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- TYPES OF INDUCED NOISE AND DESCRIPTION OF NOISE
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- VOLTAGE PARAMETERS FOR ISDN BASIC USER NETWORKS
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- 1. Purpose of this Recommendation
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- This Recommendation has been produced by CCITT Study Group V to meet the urgent requirements
- of administrations, manufacturers, and users who should evaluate equipment for its immunity to induced
- noise in order to design and use the ISDN.
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- This Recommendation identifies the types of induced noise that can cause degradation of transmis-
- sion quality and malfunction of the equipment, and noise voltage parameters that should be evaluated.
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- 2. Scope
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- This Recommendation covers the degradation of equipment performance due to induced noise volt-
- age, which is caused by an inducing source external to the cable, or by another telecommunication sys-
- tem, on metallic pair cables (including residential inside wire). However, this Recommendation does not
- cover interference caused by transmission characteristics of cables (for example, cross talk characteris-
- tics).
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- This Recommendation considers the characteristics of induced noise voltages at metallic-pair ISDN
- interfaces at subscriber's premises. Interface locations covered by this Recommendation are the S and T
- interfaces (see Recommendation I.430) as well as the two wire interface of the NT1.
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- The communication line constituting the S/T Bus may be confined to a building, or connect two sepa-
- rate buildings. The connecting telecommunications line may be either aerial or below-ground.
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- 3. Types of induced noise affecting the ISDN
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- 3.1 Mode of voltage
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- Two voltage modes should be considered: longitudinal voltage and transverse voltage. Figure 1 illus-
- trates the definition of longitudinal voltage induced in telecommunication lines and the transverse voltage.
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