Software Modems » History » Version 1
laforge, 06/29/2022 07:54 AM
| 1 | 1 | laforge | h1. Software Modems |
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| 3 | (sometimes also called _WinModems_) |
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| 5 | h2. What is a Software Modem |
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| 7 | Traditional analog modems are based around hardware modulators/demodulators, typically some kind of DSP or VLSI chipset including some kind of internal processor / software. They are basically an embedded system with two external interfaces: |
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| 8 | * the analog phone line interface |
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| 9 | * a RS-232 serial line towards a terminal or computer |
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| 11 | As desktop computers and laptops became more powerful around the turn of the century, various manufacturers started to implement _software modems_. Those modems only contained the analog line interface and an ADC/DAC. All the actual signal processing (equalizer, modulation, demodulation, coding/decoding, etc.) happened in software running on the main processor of the desktop/laptop computer (typically an x86 CPU). |
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| 13 | The related proprietary software for the main CPU was typically specific to a given vendor/chipset, and was offered in most cases only for Windows type operating systems, hence also the name _WinModem_. There were some exceptions where binary-only software was also offered for Linux or other OSs. |
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| 15 | h2. Models of Software Modems |
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| 17 | FIXME |
