Treasury bonds also pay their interest on a
semiannual basis and are sold at or near their par values.
Source
However, T-bonds have maturities that are greater than 10 years, going all the
way up to 30 years. Generally, analysts use the 10-year and 30-year yields as benchmarks when discussing the economy and interest rates. Like T-bills and T-notes, Treasury bonds are highly secure investments.
Treasury bills aren’t callable, due to their short-term maturities.
Treasury notes are also not callable. However, Treasury bonds may
be. Some longer-term bonds may be callable at par five years before
they mature. Otherwise, they aren’t callable. The fact that generally
these securities aren’t callable, coupled with their high credit rating,
makes Treasury bills, notes, and bonds an important part of some investors’ portfolios.