Abstract: A VOIP network phone forwarding device is used to forward a call of an extension to a dual-mode mobile terminal. The VOIP network phone forwarding device comprises a wireless network module, a network interface, a phone connection interface, and a processor. The wireless network module connects to a wireless network for signal transmission with the dual-mode mobile terminal via the wireless network. The network interface is coupled to a modem device for connecting to the Internet. The phone connection interface is coupled to a PBX, which is further coupled to several extensions. The processor is coupled to all the above components. When a dialing source dials a phone call to an extension, the processor forwards this call to the dual-mode mobile terminal via the wireless network or the Internet so that a user can answer this call. A mobile extension communication architecture can thus be realized to let users be able to answer any phone call anytime, anywhere.