Abstract: Network architecture for enabling a first network terminal connected in a call with a second network terminal via a first circuit, to purchase calling time during the call, the network architecture including a first network node connected to the first network terminal, a second network node connected to the second network terminal, an account management node connected to the first network node, and a call management node connected to the first network node, the account management node managing a pre-paid account associated with the first network terminal, the call management node being connected to the first network node via a signaling link, to the account management node via a communication link, and to the second network node, the call management node connecting the first network terminal with the account management node over a second circuit, while the second network terminal is on hold, whereby the first network terminal purchases calling time, the call management node disconnecting the first network ter