NO! You do NOT need Checkman software. That is used for manually running checks where you take check info over the phone and actually print out a check that you go to the bank and deposit. ECheck with Authorize.net is all electronic with payments being made just like a credit card payment. You will need to enable ECheck on your Authorize.net account which will add a little more to your monthly fee. It's $5-10 extra I believe. Thanks.