What is Asterisk ?
Asterisk is the world’s leading open source telephony engine and tool kit. Offering flexibility unheard of in the world of proprietary communications, Asterisk empowers developers and integrators to create advanced communication solutions…for free.
Asterisk® is released as open source under the GNU General Public License (GPL), and it is available for download free of charge. Asterisk® is the most popular open source software available, with the Asterisk Community being the top influencer in VoIP. Source : www.asterisk.org
In other words, you can create IVR application using Asterisk as a platform! Do they support Dialogic cards ? They support some Dialogic card but they are mainly supporter of Digium cards.
So, basically Asterisk is a linux based platform to develop CTI Applications right from low end Analog Phones to high end VoIP. They support host of protocols like their paid counter parts (Dialogic, Synway etc.) SS7, ISDN, R2MF, SIP, Speech Recognition etc.
How does it compare with traditional CTI hardware and Propritary IVR Software ?
Though it claims to be Open Source, low cost but some how I am not convinced it is an alternative of Dialogic, Synaway or other cards. Because at the end of the day, you need proper support for the hardware, plateform while you concentrate on running your business, not the IVR application.
But I am not the right person about giving any expert opinion as I am not using Asterisk. But I have started reading Asterisk and its usefulness in developing and deploying IVR Applications.
I will keep updating about Asterisk here.