Dial Dictate is difficult to set up with a Tapi modem. There are many issues to contend with none harder than:
Random tones being generated by the caller. This issue can drive you mad trying to fix.
With VOiP you minimize the random tone issues, however, I have yet to get a SIP provider set up where the system works perfect. Compounded that NCH never gives you a striaght answer makes it difficult for me to reccommend this type of system to you.