The PC speaker is normally meant to reproduce a square wave via only 2 levels of output (the speaker is driven by only two voltage levels, typically 0 V and 5 V).
For example, if your payments for March and July 2010 were each one month late, the report may continue to show (for seven years from the date after each payment was due) that you were 30 days late twice in 2010, even though the tradeline for that account also shows your payments for the rest of 2010 were made on time.
Credit Accounts How Long Do Late Payments Stay On Your Credit Reports? Late payments can be reported for up to 7 years from when the delinquency occurred. Say you missed a credit card payment several years ago, and you still use that credit card. After that late payment is 7 years old, that delinquency legally cannot be included in the history of that account on your credit report. If the account containing late payment information is closed, the entire account will be removed after 7 years.