ASIO (and ASIO 2) is an interface (audio stream input output), kind of like a driver, developed by Steinberg, that "translates" between your hardware and software; so is Direct-X, Windows MME (multimedia extensions), EASI (Logic Audio), GSIF (gigasampler), and ****loads of others... right now, ASIO and ASIO 2 happen to be the best unless you're using Logic, in which case EASI is probably just as good...
...now that we're clear on that, most cards today support the ASIO format, as well as the others I've mentioned and even a few more... in fact, you'd be hard-pressed to find a sound card or audio interface that didn't support ASIO (I don't know of any)... in case you don't know, 12ms latency is EXCELLENT, and with a few exceptions, you won't get better... the few possible exceptions are Creamware's Pulsar or SCOPE or other of their products, because they have their own DSP chips on the cards, and RME Audio's Digi and Hammerfall cards, because they have built-in ASIO hardware... finally, I think you mean A/D and D/A conversion, analog-to-digital and digital-to-analog...