software modules implement the ITU-T standards for 1200bps and 2400bps full-duplex data communication on the GSTN and on point-to-point two-wire leased line circuits. In these modems, channels are separated by frequency division and each channel is phase shift modulated. A symbol rate of 600 carries 2bits per symbol at a rate of 1200bps for V.22. For V.22bis, each channel is quadrature amplitude modulated (QAM) to carry 4bits per symbol at 600 symbols per second at a rate of 2400bps. Carrier frequencies are 1200Hz and 2400Hz respectively for the low and high channels. The software has been tested against various impairment combinations using TAS (Telephone Network Emulator). The software supports commonly used processors such as TI C5000 & C6000 series DSPs, ARM processors and ADI DSPs and OS such as Windows, VxWorks, and Linux.