Diseño e implementación de un adaptador para teléfono analógico de bajo costo

Abstract

The evolution of Information and Communications Technology (ICT) has allowed the In- ternet service to become affordable. This has allowed technologies such as VoIP to gain a place in the market. The IP telephony service has a lower cost than conventional telephony when it comes to service, however, the equipment required to make use of this service, such as IP phones and ATA devices are expensive and limited. For this reason, this project proposes to design a low cost analogue telephone adapter, that offers users a simple and economic alternative for VoIP access. The device that has been put forward must be able to provide VoIP services through a conventional telephone. In order to achieve this, it must be able to access the network, implement a coding and decoding system according to the VoIP standard, use a session initiation protocol to connect to a VoIP server and a dial-up detection system to communicate with the telephone. Since we proposed to develop an inexpensive device, we used the ESP8266 Wi-Fi module for network access. This module also implements session initiation (SIP) and voice traffic (RTP) protocols. Voice coding and decoding was performed using the A-law algorithm, which was implemented in a Microchip dSPIC33. The tests were performed by using the Elastix VoIP server.