Your Call-in PIN is a 4-digit number you supply to the customer Service representative when you call us, so we can validate your identity and customer account. Your PIN should be easy for you to remember but difficult for others to figure out and should be one that someone with access to your personal information could not guess. For example, we recommend avoiding use of your birthdate or part of your phone number, street address, or ZIP code. Also you may not use any straight numerical sequences that a malware program might attempt, such as 1234 or 1111.