56K for the Remote User

Our current modem bank of US Robotics 56K analog modems connected to a NT RAS server, only allows outside users to connect at 26K. All modem settings are configured to allow the maximium rate. We were told by our phone service provider that we needed digital modems on our end. What hardware should we be considering in order to support a full 56K connection for those remote dial-in users that do not have the benefit of broadband yet?