Patent ID: 7499729

Claim:
An apparatus designed for connecting a mobile phone and a landline communication device, wherein the mobile phone is connected to a wireless communication system and the said landline communication device does not require local phone service, the said apparatus comprising: a voice card module that regulates main AC power supply to deliver a desirable 8V DC power supply for the claimed apparatus, and to provide an analog signal path for routing voice signal between the connected landline communication device and the mobile phone earplug port; and a Central Processor Unit interfacing with a serial port or an USB port of the connected mobile phone to drive the mobile phone data modem for making outgoing phone call; and a DTMF converter and channel controller module that uses solid-state relay to interface with the said voice card module in order to correctly establish communication path between the said mobile phone and the said landline communication device wherein the channel controller module is comprised of three solid state relays, these three relays are: (a) a RVD relay that receives an 8V DC signal from a connected voice card in order to send out a 5V DC current; (b) a sensing relay that takes input signal from the RTS pin of the Central Processor Unit to send out a 5V voltage current to a channel relay; and (c) a channel relay that receives 5V or 0V DC current from both RVD relay and sensing relay to switch between OPEN and CLOSE states in order to isolate voice or fax path (PATH A) from command signal path (PATH B) to prevent mixing of analog voice signal and digital command signal.