rétrophonie

OBS: La rétrophonie permet parfois un coût plus réduit en profitant de la différence des tarifs selon le sens d'établissement de la communication.

CONT: This service, initially offered in competition to established public telecommunication operators, is now increasingly part of PTO services. Call-back can potentially offer substantial savings to consumers. Most US-based call-back services rely on uncompleted call signalling systems. This type of call-back service solicits pre-subscribed customers in a foreign country to dial a US telephone number and, after a certain number of rings, to hang up. The US call-back company then initiates a call to the foreign telephone number and when the foreign caller answers, he or she receives a US dial tone from the switch at the reseller's US location. The customer can then place a call in the United States or to a foreign destination.