My HP Designjet T120 printer is connected by cable but will not print saying is not connected.

That Apple is not as good as it claims to be!

I have had email problems and now printer problems despite downloading and installing the recent upgrade with the hope of curing the problem.

My iMac is running OSX 10.9.5 Lion and my printer is HP Designjet T120. It is cable connected as I never managed to consistently make it work wireless.

Despite that comment the printer indicated it is wirelessly connected but the computer even with cable connection says the printer is not connected. A few months ago I upgraded my CAD package of Vectorworks to 2015 from whence my printing problems seemed to start. However the Pdf printing has also gone awry. Firstly printing with all the writing on it a hieroglyphic mess and now will not print also saying the printer is not connected.

All these products are American! Are they incapable of being compatible?