Abstract: This invention overcomes the disadvantages of the prior art by providing a voice response unit that communicates rapidly and directly with a metered cellular telephone network with minimum human intervention. The rapid communication is achieved by knowing the question or prompt posed by the voice response unit and preparing a response which is speed dialed to the voice response unit. The voice response unit also calculates a check sum to determine if there is an error in the information transmitted to the voice response unit. The check sum may be the total of the absolute value of the request code, account number, serial number, access code and amount desired to be added to the cellular phone divided by ten. If, the check sum calculated by the voice response unit is not divisible by ten, the voice response unit knows that the information it received is incorrect. Then, the voice response unit would ask for the information it received to be retransmitted at a different rate of speed.