Abstract: A portable credit card terminal interface is disclosed for verifying credit information. The portable credit card terminal interface is adapted to be removably connected to a credit card terminal and to a telephone station. The credit card terminal interface includes a D/C power storage device and converter for converting D/C power from the storage device into A/C power. The device also is capable of for transmitting A/C power from the converter to the credit card terminal and detecting financial information signals representing credit and transaction information. The device further includes a first circuit for receiving from the credit card terminal the financial information signals and a second circuit for receiving from the telephone station verification signals representing verification information from a host computer. Finally, the device includes a control circuit for controlling the converter as well as for controlling both the first circuit and the second circuit means.