speech recognition accuracy with tapi via a telephone

hi guys

i am developing an application with TAPI which will receive a call and record the caller's voice and then convert it to text. but, i want to know how accurate the voice recognition can recognize the user's voice and could you recommend me to use some sort of hardware and or softwares to make the voice recognition better?

and my second question is

if i used a cellular phone connected to my application, is that possible to detect SMS messages and transfer it to my PC?

thanks and BEST REGARDS
ufancha