When we buy new device such as NEC 16D and 8D we often through away most of the documentation but the warranty.
Very often issues with NEC 16D and 8D begin only after the warranty period ends and you may want to find how to repair it or just do some service work.
Even oftener it is hard to remember what does each function in Telephone NEC 16D and 8D is responsible for and what options to choose for expected result.
Fortunately you can find all manuals for Telephone on our side using links below.