What exactly is the process involved in completing an electronic cheque transaction using ACH? From the info I've managed to gather so far, it seems there is a bank routing no. and an account no. involved. A payee should have written permission of the payor, and then the payee initiates a debit transaction against the payor's account. I would like to know in greater detail about this very process. Also, what would the details be for a credit transaction initiated by a payor?