H04M9/00—Arrangements for interconnection not involving centralised switching
H04M9/08—Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04B—TRANSMISSION
H04B3/00—Line transmission systems
H04B3/02—Details
H04B3/20—Reducing echo effects or singing; Opening or closing transmitting path; Conditioning for transmission in one direction or the other
Dispositif pour la fourniture de séries d'impulsions de courant unidirectionnelles à un circuit de charge à partir d'une source de courant alternatif.