A method and apparatus are provided for sending pulses from a sender device to a receiver device in a transmission channel. The pulses represent information symbols, with each of these pulses being associated with a time slot in a symbol time. The method includes a training step that is carried out before sending payload information and that includes sending a training sequence made up of two parts. A first part of the training sequence includes at least one pulse of energy that is greater than the energy of a pulse carrying payload information. There are a large number of time slots between the sending of the pulse and the sending of the next pulse. A second part of the training sequence includes a set of pulses known in advance and similar to the pulses used for carrying payload information, the energy of each of these pulses being equivalent to the energy of a pulse carrying payload information.