From: Bill Morrow (penzance_at_icanect.net)
Date: Tue Apr 27 1999 - 01:31:34 EDT
thats a well written discussion of Mwave, etc.
a few personal observations.. :-)
the sad fact is IBM has been slow.. in the 760 series, the Mwave did NOT
have the horsepower to do more than 33.6 and the sound, and then it was
another apparent problem is the Mwave is very critical of telephone lines
not to mention some or all digital modems used by ISP's...
in the 770 series (not sure which model if not all 770's) the Mwave now
does only the modem and there is a sound chip for the audio..
these CAN do up to 50 odd kbs.. but reality is slower.. (see above
comments irt phone lines, etc.)
the last time i did an upgrade the speed went from 33bks to 30kbs..!
hopefully, IBM will either do a real modem chipset soon, and abandon the
Mwave idea.. good as it was, it just does not seem to work as well as a
John Kim wrote:
> On Sat, 24 Apr 1999, STeve Andre' wrote:
> > Can someone explain what the MWave modem is? I have a 1451 i series
> > TP and wonder if my modem is that kind? tnx
> > STeve
> MWave is sort of the predecessor to WinModems. All modems
> have an A/D and D/A (analog-to-digital, digital-to-analog)
> convertor in them which coverts from/to the analog waveform on
> the telephone line to/from the 0s and 1s computer use. This is
> not a trivial task, and up until the early '90s was almost
> always done via hardware. The drawback of doing it in
> hardware of course is that once you mold the hardware, that's
> what it does for life.
> In the early 1990s, specialized floating point processors
> (DSPs, digital signal processors) designed specifically for
> A/D and D/A processing in software became fast enough that it
> could handle the A/D and D/A necessary in a modem (14.4 kbps I
> think was state of the art then). IBM came up with the clever
> idea of putting one of these DSPs in their Thinkpads to
> operate as a modem. The advantage being that since the
> hardware is generic, you can reprogram what it does via
> software. When a new modem standard (e.g. 28.8) comes out,
> you simply reprogram the DSP and what used to be a 14.4 modem
> is now a 28.8 modem. IBM dubbed this feature "MWave" (probably
> because the other major A/D / D/A component in computers is
> the sound input/output - or multimedia).
> Anyways, the impression I got was that IBM was having
> difficulty releasing up-to-date software drivers for the MWave
> to match the rapid advancements in hardware modems. This was
> probably coupled with the early MWave DSPs simply not having
> enough horsepower to do both 28.8 and multimedia sound at the
> same time. And apparently MWave was designed around Windows
> so supporting it under other OSes was problematic (other
> audio/modem DSPs like the one found on the TP701 do not have
> this problem). It was a good idea, but companies could put
> out new modem hardware faster than IBM could put out new DSP
> WinModems use the same concept, but use the main CPU instead
> of a DSP (yes, CPUs have gotten that fast). That's why you
> generally want to avoid them unless you don't mind the CPU hit
> and an extra 100-200 ms latency (and, as the name implies,
> they can only be used under Windows). Because they use the
> CPU instead of integrated A/D and D/A convertors, they are
> usually about $50 cheaper.
> I have no idea what type of modem the 1451i uses. IBM has had
> a bad history of releasing timely updates for their MWave (I
> don't think 28.8 was available for nearly a year after 28.8
> modems started showing up in stores), and Linux support has
> been spotty-nonexistent, so I have as a rule avoided TPs with
> MWave. But even if you do have one, you can always buy a
> PCMCIA/Cardbus modem and use it in lieu of the MWave.
> John H. Kim
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