Hi NeuralJ,
Not to prevent Jeff from answering you, but I saw that you were presenting to 5th graders, and you caught my attention. Ports and lines, huh? Sounds like you'll have some terminology to introduce. This is how we present the material, though you may want to spice it up a bit for the 5th graders.
Common terminology used with digital I/O operations:
Bit -
A bit is the smallest unit of data used in a digital operation. Bits are binary so they can either be a 1 (think of high voltage) or a 0 (think of low voltage).
Byte -
A binary number consisting of 8 related bits of data. Also used to denote the amount of computer memory required to store one byte (8 pieces) of data.
Line -
A line is an individual signal in a digital port. The difference between a bit and a line is that the bit refers to the actual data transferred, and the line refers to the hardware the bit is transferred on. However, the term line and bit are fairly interchangeable. For instance, an 8-bit port is the same as a port with 8 lines.
Port -
A port is a collection of digital lines. Usually the lines are grouped into either a 4-bit or an 8-bit port.
A picture may be worth a thousand words in your situation. Let me know if this is what you were looking for!
Chad Erickson
Switch Product Support Engineer
NI - USA
