I just checked, Windows 7 does not have the same dialer application as windows XP. Windows XP allows for full voice and contact integration, windows 7 just dials the phone. Windows 8 doesn't have either.
There are work arounds to this according to the internet, but generally speaking, MS has also long abandoned voice calls. Especially considering Windows XP is no longer supported.
The OP indicated he is in the medical industry, and this makes sense. The medical industry operates about 10 years behind the time when it comes to technology. And rightfully so, they have to move ahead securely and safely. But that doesn't mean that it commonly used outside of the industry. Example is buying houses. Around 6 or 7 years ago, you often had to fax over contracts. Now you can do most of it via email and using authorized signatures. The vast majority of industries have moved away from them, or to online services that can do the same thing.
Although I do agree that they are in use by some places, if this is something that the OP was required to have; then he should have really spent some time verifying that it can do this job before plopping down his money. The problem is finding a current windows machine that can do it; without having to buy an external modem and 3rd party software.
Moving ahead with technology is very important, being tied to old items, regardless of their usefulness, can cause tons of problems. Yes, there are people out there that still use Windows 16 bit applications; and thus they stick with their old OS. I worked with a company that still ran their production lines on Apple IIe's; they had a stock of them for when one broke. Does this mean that Apple should keep making them? Heck no.
Years ago I worked for a company that made components for PC's. This was during the windows '95 era. We had a customer complaint that we didn't supply CPM drivers for our hardware. Not DOS, but CMP! Seriously the guy sounded just like the OP; there are tons of people using CMP and if you don't support it well you'll just go out of business. We later discontinued our DOS driver support, and had the same series of calls. Eventually the company was purchased by a much larger one.
The point is, often people don't see beyond their current needs, and assume that everyone else's needs are the same. They aren't. Progress has to be made, industries HAVE to move forward or fade away into obscurity. It is their job to predict the future, and move toward it. It is the consumer's job to follow or stick with what they are comfortable with, but if they chose the latter they have to realize that at some point, they will be obsoltetted.