H04M3/42—Systems providing special services or facilities to subscribers
H04M3/50—Centralised arrangements for answering calls; Centralised arrangements for recording messages for absent or busy subscribers ; Centralised arrangements for recording messages
H04M3/51—Centralised call answering arrangements requiring operator intervention, e.g. call or contact centers for telemarketing
Contact equipe d'un compensateur magnetique autoliberable a partir d'un seuil de force de compensation, et contacteur-disjoncteur utilisant un tel contact