Beaware of Soft Modems

When you buy your next modem, you could innocently buy a software-based modem, not realizing the limitations of what you're buying.

Why soft modems are different ?

Software-based modems use fewer chips compared to traditional modems. The work normally done by the missing chips is transferred to software running on the host computer's main processor.

Modems consist of two major components

A datapump performs the basic modulation/demodulation tasks for which modems are named
A controller provides the modem's identity: this is where the protocols for hardware error correction, hardware data compression, and basic modulation protocols (such as V.34, x2 or K56flex) exist. The controller is also responsible for interpreting AT commands.
A traditional modem implements both features in hardware, as chips inside the modem.

An HSP modem dispenses with both the controller and the datapump, and uses software to provide both functions. Short for host signal processor, HSP modems transfer the work normally done by the missing chips to software running on the host computer's main processor

How do you know if it's a software modem?

There are a number of clues that your modem is software based:

If a modem is shows Windows-only, it is probably software-based.
The phrase "controlless modem" isn't just a clue: it's an absolutely accurate description. Few commenly available modems are Intel R53, Motrolla SM56, PCTel, MR56K etc.

Intel chipset most popular software-based modems. Using the fame of Intel few vendors selling the modem with label of Intel. Intel has already published aids in news papers that this modem does not belong to Intel.

There are a number of flaws in the soft modem concept. In all cases, your host computer has to do more work to make up for the modem's lack of hardware. One RPI modem user reported slow transfer rates and dropped connections until he upgraded his PC from eight to sixteen megabytes of RAM (which improves performance in Windows).

The other big disadvantage of software-based modems is that the software needed to make them work is operating-system dependent.

Winmodem configuration can be messy, because Winmodems use a range of memory addresses instead of a fixed memory address. Winmodems require a DLL file that loads into memory at startup, using some of Windows' resources.

If software-based have these problems, why do they continue to sell? In part, the answer is cost. By omitting a few chips, manufacturers can sell Winmodems for twenty to fifty dollars less than traditional modems. In an era of thousand dollar PCs and handheld consumer devices, cost is an enormous issue.

In general, we recommend avoiding HSP modems. Get a good old-fashioned modem with all of its chips intact. Nothing else offers the same level of reliability, compatibility, and performance. The small savings of buying a Winmodem doesn't compensate for the load it shifts to your expensive new Pentium.