We are offering sip phone. Grandstream, panasonic, nec , and matrix the gxp series of color-screen ip phones offers 3, 4 and 6 line ip phones with a suite of advanced voip calling features to maximize enterprise productivity and communication. Features such as hd audio support, a full color-screen operating system, various blfspeed dialextension module options and built-in bluetooth offers users a powerful desktop experience.