This Recommendation provides a flexible mechanism for digital subscriber line (DSL) transceivers to exchange capabilities and to select a common mode of operation. It includes parameters relating to service and application requirements as well as parameters pertinent to various DSL transceivers. This Recommendation is currently an integral part of the start-up procedure for ITU‑T Recommendations G.991.2, G.992.1, G.992.2, G.992.3, G.992.4, G.992.5, G.993.1 and G.993.2. It is anticipated that future DSL Recommendations will also be able to make use of this Recommendation. Provisions are also included for exchanging non-standard information.

This version also includes the following:

G.994.1 new Amendment 1 for consent 06/2007, which includes:

Support for Amendment 2 to Recommendation G.998.2

Support for exchange of transmit and receive levels of individual carriers

Support for Amendment 4 to Recommendation G.992.3 (new Annex C parameters)

Support for Amendment 4 to Recommendation G.992.5 (new Annex C parameters)