Why did Rockwell introduce RPI technology?
RPI lowers the cost of traditional modem hardware by redistributing the Error Correction and Data Compression (ECC) processing load from the modem to the host computer, eliminating the need for external memories (RAM and EPROM) and allowing lower cost controllers to be used. This drive to lower the component cost was strongly driven by modem vendors desiring to offer the lowest possible end user price. It also lowers the interrupt rate to the operating system (OS), as only precompressed data is sent on the COM port, unlike hardware ECC modems, which send uncompressed data over the serial port. If the data is compressible at a ratio of 2 to 1, which is very likely with ASCII text, then an RPI modem interrupts the OS approximately 50% less than a hardware ECC modem would.
