Design Of ARM-Based Remote Control Terminal Of Public Switch Telephone Network

With the rapid development of modern communication technology, PSTN also develops rapidly and covers many districts. Because of PSTN's high speed and reliability, and without occupation of transmission line and frequency, remote control technology of PSTN is an economical and effective mode.At present, most remote control technology of PSTN adopt DTMF signal to communicate within remote control terminals. However the transmission speed of DTMF signal is slow and terminal mostly use 8bit-MCU, remote control terminal is usually designed to only receive data because of poor capability of 8bit-MCU, and not to transmit any data. As a result it couldn't form feedback and limits the use of remote control technology of PSTN at the same time.To make up the shortcomings above and take account of market's requirement and embedded system's rapid development simultaneously, author designs an ARM-based remote control terminal of PSTN in this paper. It makes use of ARM processor and RTOS to constitute a platform, user can develop application on it. The platform also affords convenience of upgrade and maintenance of remote control terminal, at the same time could meet requirement of market.The contributions of this paper are:1. The real-time kernel μC/OS-II is ported to ARM successfully, thus a universal embedded real-time platform is built.2. The remote control terminal depends on the excellent performance of ARM processor. Terminal implements DTMF's transmission and V.22bis modem standard, and meets mass data transmission. Accordingly, the remote control terminal forms feedback, thus constitutes a complete communication system.3. In order to improve the security of transmission, the remote control terminal implements DES algorithm to encrypt important data based on DTMF such as password, thus it ensures the reliability of system.