Below is the comparison table regarding how the modems process the data for controller-based modem, controller-less modem and software modem.
Comparison Table of Controller-based modem, controller-less modem and software modem.
| |
Controller-base Modem |
Controller-less Modem |
Software Modem |
| Command Protocol |
Micro-controller |
Host-CPU |
Host-CPU |
| Command Interpreter |
Micro-controller |
Host-CPU |
Host-CPU |
| Virtual Comport |
Micro-controller |
Host-CPU |
Host-CPU |
| Error Correction |
Micro-controller |
Host-CPU |
Host-CPU |
| Data Compression |
Micro-controller |
Host-CPU |
Host-CPU |
| De/Modulation |
Data Pump |
Data Pump |
Host-CPU |
| A/D, D/A Converter |
Codec(AFE) |
Codec(AFE) |
Codec(AFE) |
| Echo Cancellation |
Codec/DSP |
Codec/DSP |
Codec(AFE) |
The difference between these three types of modem are the way they process data. Usually, Controller-less modem and software modem can provide more competitive prices for the same functions compare to controller-based modem. But, it will burden your system's CPU and slow down the processing speed. By contrast, controller-based modem has higher price tag, but it offers you efficient multi-task to save your time. In addition, software modem has narrow compatibility with different BIOS code. Furthermore, the increase of CPU loading will cause more interruption, DSP code will occupy higher percentage of SDRAM and the larger driver will also burden the memory, therefore, more errors might occur in such conditions. That is, you will encounter some compatibility problem during installing this type of modem if you purchase it seperately in the retail stores. Also, your computer will more often shut down owing to more errors occur. Usually, these modems are bundled in the computer or sold to the system integrators and shipped out in an entire system to prevent the compatibility problem. That is why end users seldom see these modems put on the shelves.