Does anyone know what specific USB cable I need for a Vivitar 3915 digital camera? I bought it without the usb cable and the port is too small for other usb cables that I have for a Canon. From what I can research, it appears to be a "mini-B" but I don't know if that's a 5 pin or 4 pin. The 4 pin looks like it would wrok but I hate to assume it. Thanks in advance for any help.