MINNEAPOLIS – In an effort to draw more ATM users and keep up surcharge income, US Bancorp has announced that it has begun upgrading its 4,600 ATMs to allow consumers to recharge their pre-paid cell phone accounts at their machines. More than 4,000 of the machines have already been upgraded and the customer response has been strong, according to the company. The bank has partnered with Boston Communications Group to offer the service. The transaction is much like a standard ATM transaction. A cardholder approaches the ATM, swipes the card and enters a PIN. The option screen includes the choice of refilling a prepaid cell phone. The cardholder enters their phone number and the amount they want to add to the phone. The ATM checks with the provider to make sure the number is valid and then makes the transfer. The bank gets a fee from the phone provider but not from the cardholder.