The coupons were presented to the bond issuer to make it collect periodic interest payments.
The COUPDAYS function returns the number of days in a coupon period that includes the settlement date.
The settlement date is the date the investor takes possession of a security.
Thefrequencyis the number of interest payments per year.
Entering dates
In Excel,dates are serial numbers.
To enter valid dates directly, you’ve got the option to use theDATE function.
Basis
Thebasisargument controls how days are counted.
The COUPDAYS function allows 5 options (0-4) and defaults to zero, which specifies US 30/360basis.
Thisarticle on wikipediaprovides a detailed explanation of available conventions.