The 73M2901CE supports an optimized version of the industry-standard Hayes AT command set. The primary distinction between the Hayes AT command set and the 73M2901CE AT command set is in the use of the & (ampersand) command. The 73M2901CE does not use the & command. Many 73M2901CE commands relate directly to the Hayes & commands, but this is not always the case. For example, the 73M2901CE ATC[n] command is similar to the Hayes AT&C[n] command, but it is not identical. This document makes users aware of these differences.