The transmit and receive functions are called within a single function called V32_isr. This function is called to process received samples and to generate
samples to transmit. The V32_init function is called to initialize the V.32/32bis modem. This function initializes the structure which contains all the memory required for the modem. The V.32/32bis
modem can be adapted for a variety of sampling rates such as 9600 Hz or 7200Hz. The V.32bis/V.32 modem is designed to process data in 10ms intervals.
Features of V.32/V.32bis Software (Softmodems V.32/V.32bis)
Full duplex mode of operation on switched and 2 wire, point-to-point, leased circuits.
Channel separation is accomplished using echo cancellation techniques.
QAM is used for each channel, with synchronous line transmission at 2400 baud.
Data signaling rates: 14400, 12000, 9600, 7200, and 4800 bps synchronous.
Trellis coding at rates from 7200 to 14000bps for V.32bis.
For V.32, two alternative modulation techniques are used for a signaling rate of 9600bps, one uses 16 carrier states and one uses trellis coding with 32 carrier
Exchange of rate sequences is provided during start-up to establish the data rate, coding, and any other special facilities.
The frequency carrier operates at 1800Hz.
Transmitted power levels conform to V.2
The modulation rate is 2400 symbols.