Typically available as an external USB module, for desktop computers, the modem may also be available on a PCI or PCI Express (PCIe) card that plugs into an empty slot on the motherboard.

It’s actually a fairly straightforward hack. The Mini PCI-e standard has a couple of pins dedicated to USB data lines, which the modem in question uses for communicating with the host computer.

In 2000, AMD, 3Com and others introduced ACR to supersede AMR. Taking up one PCI slot, it accelerated audio and modem functions in hardware. For audio and modem only, it could be built with a ...