An electronic device comprising: first and second printed circuit boards; and a flat flexible cable assembly for electrical signal transfer between the first and second printed circuit boards, the flat flexible cable assembly having a first end connected to the first printed circuit board, a second end connected to the second printed circuit board, and a central flexible cable portion between the first and second ends, wherein the central flexible cable portion characterized by: an electrically insulating substrate having a thickness selected to control a target impedance to support unattenuated signal transfer associated with a protocol faster than 100BASE-TX Ethernet; a first layer of metal on the electrically insulating substrate, the first layer being a ground; a dielectric continuous layer on the first layer of metal having a thickness selected to control the target impedance to support unattenuated signal transfer associated with the protocol faster than 100BASE-TX Ethernet; a second layer of metal on the dielectric continuous layer, wherein the second layer is divided into individual conductive lines separated by insulating gaps and the conductive lines transfer the electrical signal; and a protective coating layer on the second layer of metal. first and second printed circuit boards; and a flat flexible cable assembly for electrical signal transfer between the first and second printed circuit boards, the flat flexible cable assembly having a first end connected to the first printed circuit board, a second end connected to the second printed circuit board, and a central flexible cable portion between the first and second ends, wherein the central flexible cable portion characterized by: an electrically insulating substrate having a thickness selected to control a target impedance to support unattenuated signal transfer associated with a protocol faster than 100BASE-TX Ethernet; a first layer of metal on the electrically insulating substrate, the first layer being a ground; a dielectric continuous layer on the first layer of metal having a thickness selected to control the target impedance to support unattenuated signal transfer associated with the protocol faster than 100BASE-TX Ethernet; a second layer of metal on the dielectric continuous layer, wherein the second layer is divided into individual conductive lines separated by insulating gaps and the conductive lines transfer the electrical signal; and a protective coating layer on the second layer of metal. an electrically insulating substrate having a thickness selected to control a target impedance to support unattenuated signal transfer associated with a protocol faster than 100BASE-TX Ethernet; a first layer of metal on the electrically insulating substrate, the first layer being a ground; a dielectric continuous layer on the first layer of metal having a thickness selected to control the target impedance to support unattenuated signal transfer associated with the protocol faster than 100BASE-TX Ethernet; a second layer of metal on the dielectric continuous layer, wherein the second layer is divided into individual conductive lines separated by insulating gaps and the conductive lines transfer the electrical signal; and a protective coating layer on the second layer of metal.