Similarities
Both codes are similar insofar as they attempt to encourage specific forms of behavior by employees. Ethics guidelines attempt to provide guidance about values and choices to influence decision-making, whereas conduct regulations assert that some specific actions are appropriate or inappropriate. In both cases, the company's desire is to obtain a narrow range of acceptable behaviors from employees.
Differences
The codes attempt to regulate behavior in very different ways. Ethical standards generally are wide-ranging and non-specific, designed to provide a set of values or decision-making approaches that enable employees to make independent judgments about the most appropriate course of action. Conduct standards generally require little judgment; you obey or incur a penalty, and the code provides a fairly clear set of expectations about which actions are required, acceptable or prohibited.