# Transposed Direct Form II

In the book digital Signal Processing by Proakis 4th Edition, at page 593 a table is drawn about some second order modules for discrete time systems. In that table there Transposed Form II drawn But when I searched the net, it was drawn completely opposite to that drawn in the book. On the internet, the input and output were placed on right and left respectively. I want to ask that which form is correct?

Direct-Form II is the canonical structure to implement an LCCDE, using minimum number of delay elements and multiplications. The input $$x[n]$$ is placed on the left, and the output $$y[n]$$ is on the right, complying with the signal processing conventions.
However, for convenience, to comply with the convention that the input is applied at the left node, the transposed DF-II structure is horizontally flipped. This way, input $$x[n]$$ appears at the left again.