There are two different configurations of Scott's Binary Clock: BCD mode and binary mode. Scott's Binary Clock can display the clock in several different formats (the columnar format below being just one of them). There is also a horizontal format that displays each digit as a row.

BCD mode is the more common mode and is what you would probably find if your bought a real "hardware" binary clock from a gadget store. Scott's Binary Clock version 1.6 and newer automatically defaults to BCD mode. BCD mode is the easier of the two modes to interpret and is described below.

The key to BCD mode is that it splits each number into two digits, making them easier to read. In the example above, the "18" was split into "1" and "8", and the "1" and the "8" were each encoded seperately.

The picture below demonstrates how to read a binary clock in what I would call "true binary mode". True binary mode is for diehard binary clock users who want to make the clock as hard to read as humanly possible.:) It's also the most accurate representation of how numbers are stored in your computer.

Each LED represents a power of two. The lower-right LED represents "1", the LED above it represents "2", etc. All you do is add them up to get a total for the digit. Note that since the maximum number of minutes in an hour is 60, there is no way to light up the 64 or 128 LEDs in each segment.

So which mode should use use? Binary or BCD?

bcd mode: easier to read used in older (1970's era) computers looks like most "hardware" binary clocks that you might buy in a store

binary mode: more difficult to read used in today's modern computers