What code is used when sending CW in the amateur bands?

The correct code used when sending Continuous Wave (CW) signals in the amateur bands is International Morse code. This code is a system of dots and dashes that represent letters, numbers, and punctuation, allowing for the transmission of messages over radio waves. The simplicity of Morse code makes it highly effective for communication in low-signal conditions, which is one reason it has become a staple in amateur radio.

International Morse code is standardized and recognized globally, enabling operators from different countries to communicate despite language barriers. The ability to send and receive messages via sound pulses or light flashes makes Morse code a versatile form of communication.

The other codes listed are not suitable for CW communications. Baudot is a character encoding for telegraphic transmission, Hamming is related to error detection and correction in digital communications, and Gray code is a binary numeral system that ensures only one bit changes at a time. None of these codes are used in the context of transmitting information via CW in amateur radio.