The single-chip MODEM majors in MCU control system. This paper introduced the fundamentals of the chip, the interface circuit linking 73K222AL and AT89C51, and its programs.
文章分析了它的主要特性，同时给出了73K222AL与单片机AT89C51的接口电路和应用程序设计。
2
This papers is about the design of the interface based on the modem ST7538 , measuring and analyzing the performance of the interface.
本文根据选用的调制解调模块ST7538设计了一种接口电路并对它的性能进行了测试分析。
3
Also, this PLC transparent modem optionally supports RS-485 interface for compatibility reasons.