© National Instruments | 3-25NI 651x User ManualNI 6515 Signal DescriptionsTable 3-6. NI 6515 Signal DescriptionsPin Number Signal NameInput orOutput Signal Description1, 2, 3, 4, 5, 6, 7, 8 P0.<0..7> Input Data lines for port 09, 10, 11, 12 P0.COM Input Common lines for port 051, 52, 53, 54, 55, 56, 57, 58 P1.<0..7> Input Data lines for port 159, 60, 61, 62 P1.COM Input Common lines for port 113, 14, 15, 16, 17, 18, 19, 20 P2.<0..7> Input Data lines for port 221, 22, 23, 24 P2.COM Input Common lines for port 263, 64, 65, 66, 67, 68, 69, 70 P3.<0..7> Input Data lines for port 371, 72, 73, 74 P3.COM Input Common lines for port 325, 75 NC — No connection26, 27, 28, 29, 30, 31, 32, 33 P4.<0..7> Output Data lines for port 434 P4.COM (VCC) Input Power line for port 435, 36, 37 P4.GND Input Ground for port 4;isolated from thecomputer power supply76, 77, 78,79, 80, 81, 82, 83 P5.<0..7> Output Data lines for port 584 P5.COM (VCC) Input Power line for port 585, 86, 87 P5.GND Input Ground for port 5;isolated from thecomputer power supply38, 39, 40, 41, 42, 43, 44, 45 P6.<0..7> Output Data lines for port 646 P6.COM (VCC) Input Power line for port 647, 48, 49 P6.GND Input Ground for port 6;isolated from thecomputer power supply50 P6.+5V Output +5 V for port 688, 89, 90, 91, 92, 93, 94, 95 P7.<0..7> Output Data lines for port 7