1. A method of transmitting voice frames by a transmitting terminal, said transmitting terminal comprising: means for generating at least one voice frame from a voice signal, each voice frame comprising voice data; means for transmitting said at least one voice frame to at least one receiving terminal, via a transmission channel reserved for voice data, wherein said method comprises the following steps: obtaining configuration data relative to transmission of non-voice data over said reserved transmission channel; obtaining non-voice data; and for each voice frame generated by said means of generating: selecting at least one piece of voice data among the voice data of said voice frame, said selecting being carried out as a function of said configuration data; constructing a degraded voice frame by replacing said at least one piece of selected voice data with at least one of said pieces of non-voice data; inserting a non-voice data header into said degraded voice frame, said header comprising said configuration data; and transmitting, to the receiving terminal, said degraded voice frame including said header, via said reserved transmission channel.