(RPI) A cost-cutting feature of some modems allowing data compression and error correction (e.g. itu-t v.42bis, v.42) to be provided in software instead of hardware.

Usually an RPI modem comes with RPI-aware software (e.g. the low-end RPI models of Supra come with the comit which supports RPI, providing mnp 2,4,5,7, V.42 and V.42bis). RPI is not supported by many commercial packages nor by current releases of popular shareware communication programs (telix v3.22 and telemate v4.12). procomm plus for windows 2.0 will support RPI.

Currently rockwell produce two classes of RPI chip set. The original is capable of 2400 bit/s data, 9600 bit/s class 1-only fax. The newer one is capable of 14400 bit/s data/fax. Currently there are no RPI chipset from Rockwell supporting speeds higher than 14400 bit/s.