Abstract: An input/output electrical connector header 102 includes at least two rows of terminal pins 140 which can be connected to two separate printed circuit boards 106 and 108. The same header 102 provides input and output for both printed circuit boards 106, 108. The terminal pins 140 in each of the rows extend through openings 130 in the same header housing wall 126. A separable interconnection is made between pins in a second terminal row and a second printed circuit board 108 at the rear of the header 102. This separate connection can be established by a separate multiposition connector 114, 214, 314 or 414 containing receptacle contacts 116, 216, 316, 416 respectively. In other embodiments, this separate connector 514, 614, 714 and 1214, includes the terminal pins in the second terminal row in the separate connector.