I can't speak to the differences between the HAL and HS PCI modems (I'm using a Way-2-call myself), but a major factor in overall modem cost is the basic modem architecture. "Winmodems" use the main CPU for processing, and work only on machines running a MS OS (I have seen a "Winmodem" for Linux recently though). Basically, the software is doing all the work, and thus it does chew up a percentage of CPU cycles. "Normal" modems have hardare on the board to do the processing, thus the extra cost. They can be used with any OS, and demand less from the CPU.