The short version is that there are no free Conexant drivers for Linux. (Unless something has popped up in the last few days, of course.)
Your choices are limited if you want to use the modem, either pay for the driver, or you can use an external modem. External modems almost always work, especially if you have a serial port on the laptop to hook it up to. Some USB externals will work also, but you have to be VERY careful about which one you buy as not all of them are supported.