The present document gives guidance on a common language for Spectral Management specifications. It provides a set of definitions on Spectral Management quantities, including:

a) a description of the technical purpose of Spectral Management;
b) a common reference model to identify LT-ports, NT-ports, upstream, downstream, etc.;
c) a minimum set of characteristics necessary to describe signals within the context of Spectral Management; and
d) an informative library of electrical signals that may flow into the ports of a metallic access network.

The present document is applicable to simplify and harmonize the description of network specific Spectral Management documents. The objective is to be a clear reference for these documents, without making any specific choice on the technology mix that may use the access network. Network specific documents, that rule the cable fill and technology mix for Spectral Management purposes, can be kept compact by referring to the definitions in the present document.

The informative library of signal definitions is organized in clusters of signal categories. Each category defines, independent from other categories, a full set of signal limits between DC and 30 MHz. These categories are dominantly based on transmission equipment standards from ETSI and ITU (existing or in progress), and on the technical understanding of additional requirements to protect future technology. When these definitions are incomplete or not appropriate, network specific spectral management documents may use additional definitions.

The characteristics of each signal described in this signal library identify their absolute maximum (or minimum) values. They fully account for the spread in their actual value, unless this tolerance is explicitly specified. This means in practice that when a power limit of a signal category is specified by a single number (for instance 14 dBm), it refers to its nominal maximum power plus its tolerance (for instance +13,5 dBm ± 0,5 dBm). This approach provides clear criteria to determine if a signal under test is compliant or not with a signal category from this library.

The intention of the present document is to present a set of signal descriptions from various sources collected into a single document. Some of the descriptions have their origin in xDSL related ETSI and ITU publications and some are completely new. Detailed references have been included where applicable.

Due to differences in the way these signals are described in the different sources, the description has been harmonized into a uniform format. This enables a unified signal specification method for spectral management purposes. It should be noted that, although this unification has been carried out with the best intentions, and with the best knowledge available, some content of the original source document may not have been correctly interpreted or copied into the present document.

In the case of discrepancies between a signal description in the present document and the original source document(s), the source(s) should be regarded as definitive. Therefore the content of the present document should be regarded as informative.