Abstract: Network-units (1) comprising modems (2) and agents (5) give their modems (2) a larger freedom by supplying a mask or a set of masks from the agent (5) to the modem (2), which mask or set of masks defines extreme parameter values such as extreme values of power spectral densities, and by letting modem controllers (50) control parameter values such as values of power spectral densities in dependence of the mask or the set of masks. The modems (2) can then efficiently comply with a standard that specifies a set of tests to be passed by the power spectral densities to be transmitted by the modems (2). Modem information such as usable and un-usable tones are supplied from the modems (2) to the agents (5) to let agent controllers (50) control the mask or set of masks in dependence of the modem information. Modem selectors (30) and agent selectors (60) select one or more masks. Modem calculators (31) and agent calculators (61) make calculations.

Abstract: A telecommunication arrangement with modems (MCO; MCPE) having a receiving module (URx; DRx) able to receive channels of signals via a communication line (LN). The arrangement preferably operates according to the xDSL protocol. The receiving module of each modem is associated to storage means (USN, DSN; LDN) storing a “channel condition model” corresponding to operational conditions of the channel, preferably to the “worst case”. The channel condition model is determined by previously measured operational conditions of this channel and/or by a channel condition model managed externally to the modem, and which is stored in the storage means before the initialization of the modem. In different variants, the channel condition model is a model of the noise level, the signal-to-noise ratio, the actual or the maximum bitloading (bi) per carrier of the channel and/or mathematical operations on these. The channel condition model is further updated at regular time intervals during initialization or showtime.