The Ortho mode is available via the icon 
in the status bar or the hotkey F8. The command switches on/off the mode of orthogonal drawing. When this function is on editing the objects with the help of the modifying instruments and creating linear entities are fulfilled strictly horizontally or vertically along the plane XY. The Ortho and the Polar tracking modes can't be used simultaneously, that's why while switching the ortho mode on the polar tracking mode is automatically switched off.
The set deviation angle from the X axis of the element under creation defines the angle explicitly and has a priority over the mode of orthogonal drawing.