We have a much different setup in our office, we have conencted DialDictate to our Cisco IP Phone system and all of our doctors dictate using the phone on thier desks and the dictation gets sent to our transcriptionists right away. I have to say, I downloaded the demo, tested it for a week, got the setup working perfectly, bought it, and haven't had a second thought over the last year of it's use.
Setting it up with one line and modem for a doctor should be pretty simple since you don't have to tie it into and exisiting phone system. This software is very flexible and with Express Scribe being free you only have to buy the DialDictate software. I would definately recomend that you give it a try.