When the printer is attached directly to the modem without any desktop/Laptop in between other laptops on the same wi fi network recognise it as a network printer at ip address \\http://192.168.1.1/631/hp.Apps such as printershare allow my android to send print command to a network printer attached to my desktop to which the printer should be connected but that requires the desktop to be continuously switched on. .There must be some tweak in the system to allow the print command to be send directly to the modem which sends it to the printer..like it does when i send a command from my laptops.