scope:

This Recommendation covers the degradation of equipment performance due to induced noise voltage on metallic pair cables (including residential inside wire), which is caused by an inducing source external to the cable or by another telecommunication system. However, this Recommendation does not cover interference caused by transmission characteristics of cables (for example, cross talk characteristics).

The 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 2-wire interface of the NT1.

The communication line constituting the S/T bus may be confined to a building or connect two separate buildings. The connecting telecommunications line may be either aerial or below-ground.

Purpose of this Recommendation

This Recommendation has been produced by 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.

The Recommendation identifies the types of induced noise that can cause degradation of transmission quality and malfunction of the equipment, and the noise voltage parameters that should be evaluated.