What are the guidelines for the voicemail password?

Your voicemail password must meet the following guidelines:

1. Must be between 5 and 15 digits
2. Cannot use sequential numbers (e.g. 123456)
3. Cannot use your extension number
4. Cannot use the same number 5 times (e.g. 44444)
5. Must contain three unique digits.
6. Cannot use your last three passwords