I have a US Robotics V92 fax pci modem, controller based, which is about 10
years old. Is it considered obsolete?
In a snobbish "if you can't buy the exact same thing new
anymore", kinda way, maybe. There's probably something very
similar you can still buy new though, so this is a grey
area.
In a "does it do the job as well as the other alternatives"
kinda way, it depends on your specific needs.
A controller based modem is desirable in that it uses no
software to work, no CPU overhead, no operating system
dependencies for that driver, and overall most people would
be better off using one.
A controllerless is cheaper, smaller, and uses a slight bit
less power. Being cheaper it obviously became more popular,
even moreso as systems became fast enough that they had
ample spare CPU cycles.
If so, what would be a good replacement, still keeping with dialup mode?
If it works fine there is no reason to replace it, you'd end
up with a downgrade.
Would there be any advantage with a USB external modem?
Absolutely not. 'Tis the worst choice.
Are you a masochist? I ask because you seem to have a
tendency to want to change something that (AFAIK) works
fine, without reason.
You didn't even mention your needs for this modem so the
whole post was a bit wasted... without a purpose, you need
no modem at all.