5 Sep
2009
5 Sep
'09
12:10 a.m.
Fred Cisin wrote:
Unless you are going for some ridiculously high speed,
like over 300 bits
per second, that wouldn't work with acoustic coupling, why would you need
a DAA?
You need something to provide galvanic isolation, hook switch control,
ring detection, and transient voltage protection. It's possible to do
all those with your own circuitry using one or more transformers,
capacitors, or optoisolators, or a combination thereof, along with
various linear circuitry. Of course, even if you build it yourself,
it's a DAA. Much easier to buy a module or chips. If you're designing
a high volume cost-sensitive product, the module probably won't be
cost-effective, but the chips probably will.
Eric