[CentOS] finding the right serial port, enabling & configuring it [was: Re: fax software]

[Robert Heller]

At Tue, 29 Mar 2011 12:47:50 -0400 CentOS mailing list <centos at centos.org> wrote:

> 
> >> ....I also have a PCMCIA slot and an old modem
> >> card from a previous laptop, so that might be a better option than
> >> wrestling with a winmodem.  I don't know yet....
> > 
> > The old PCMCIA modem card might not be a fax modem.  If the laptop does
> > have a "good old" DB-9 serial port connector, then going to Best Buy
> > (or CompUSA, etc.) and getting something like a Creative Blaster analog
> > RS232 serial modem might be also quite easy and painless.
> 
> I have a strong aversion to external peripherals dangling off a box...
> looks too much like a high school science project.  And external modems
> are known to get very hot.  I used one somebody gave me to keep my
> coffee cup warm.  :)

Oh, internal modems *also* get hot -- this is not something partitular
to external modems -- 'real' (hardware) modems (internal or external)
have lots of analog circuts including resistor networks that get hot --
this is part of dealing with analog phone lines, which are still very
19th century in their signaling methods (eg voltage and current
levels).  And a cooking internal modem can cause other problems, like
fried motherboards... One *major* advantage of an external modem is
that it can be disconnected, turned off, unplugged, etc. without
shutting down the host machine (ditto for reconnecting). Sometimes
modems (internal OR external) become confused and need to be
'rebooted'.  With an external one, this just means flipping the power
switch on the modem, with an internal one it means rebooting the system
(which is not always convenient).

If all you are doing is the occassional faxing, leave the external
modem off, unplugged, and stashed on a shelf.  Oh, and it will be less
bulky than a all-in-one printer or a real-live fax machine (imagine
lugging something like that around).  I expect that unlike me, you
don't depend on dial-up internet access, so the external modem is not
going to be an essentual external peripheral.

> 
> That Blaster is pretty much the internal modem I had in a previous
> machine I built.    Maybe I should just revive that old dog with a new
> motherboard and CPU.  But hmm, I think that Blaster card needed an ISA
> slot.  Don't know if new mobos have those anymore.  (?)

Unless you spend serious bucks, ALL *PCI* modems are win modems (there
are one or two very high-end 'industrial grade' PCI 'hardware' modems).
Many older *ISA* modems were 'hardware' modems and were meant for old
i586 and i486 systems that lacked the CPU cycles to handle a
controllerless modem (winmodem).  And ISA slots are pretty much
non-existent on modern motherboards.

> 
> Robert, you're probably right all 'round.
> 
> Thanks.
> 
> 
> 
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>                                                                        

-- 
Robert Heller             -- 978-544-6933 / heller at deepsoft.com
Deepwoods Software        -- http://www.deepsoft.com/
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