How to use this Java script:

1. Enter a sequence of 12 bits in the first text field. This is the sequence of 12 information bits you want to transmit from one party to another party. Make sure your input is a sequence of 12 bits Otherwise you will get an error message when you try to encode it.

2. Click the "Encode" button. The Golay encoding algorithm codes the input sequence of 12 bits to a sequence of 24 bits. Notice that the first 12 bits of these 24 bits are exactly the 12 information bits. The coded sequence of 24 bits is transmitted over a channel to a receiver at the other end of the communication system. When you click the "Encode" button, the coded sequence of 24 bits appears in both the second and the third text fields.

3. Introduce bit errors in the 24 bits received. You do this by flipping bits in the third text field. The Golay coding can detect up to 4 bit errors in 24 bits, and can correct up to 3 bit errors in 24 bits.

4. Click the "Decode" button. The Golay decoding algorithm tries to detect the bit errors occurred in the 24 bits received.
   • If the 24 bits received have <= 3 bit errors, the Golay decoding algorithm detects the actual bit errors occurred and recovers the 24 bits that were meant to be transmitted. The error pattern detected is shown in the fourth text field. The 12 information bits recovered are shown in the fifth text field.
   • If the 24 bits received have 4 bit errors, the Golay decoding algorithm is capable of detecting that 4 bit errors occurred but cannot determine the error pattern occurred. It issues an error message.
   • If the 24 bits received have > 4 bit errors, the error pattern detected by the Golay decoding algorithm is not the actual error pattern occurred, and consequently the 12 bits recovered are not the same as the 12 information bits.