V.8 has been built flexible, and can be easily upgraded in the future if the need arises. It allows the v.34 modem to intelligently choose the optimum operating parameters for any given telephone channel. Line Probing is a bi-directional exchange which is performed immediately after v.8 negotiation and involves the transmission of complex signals that allow the distant receiver to analyse the characteristics of the telephone channel before entering data transmission. Sets optimum bandwidth and placement from 11 combinations with 6 different symbol rates, each with 2 possible carrier frequencies - Pre Emphasis Selection. Modems choose the optimum transmit pre-emphasis filter from menu of 10 defined filters.
Modems choose the optimum transmitter output power level.
The line probing features are performed on initial connecting and when ever line conditions change, which is very handy if your connection for periods of time, especially over leased lines or microwave links. This is an amazing feature which can compensate for known channel distortions learnt during Line probing. The modem has a selection of 10 different filters to choose from so that it can get the signal though as best as possible to the receiver. Adaptive power control is an intelligent, adaptive scheme which automatically selects the optimum transmit level based on line probing results. The effective coding gain of the three new v.34 codes employed work to be the best trade-off between performance, delay and complexity.