Abstract: A device that links a telecommunication device (for example a data terminal, a telephone instrument, a message terminal or a video terminal) directly to a telephone line for cancellation of a call waiting tone. When an incoming call is received by the linked telecommunication device, the device according to the invention places the interface terminal on hold while maintaining it on line, while a special call waiting cancellation DTMF code such as "*70" is generated and transmitted. Following this action, telecommunication device is returned to the line and the original transmission is allowed to resume.