There are many interesting simulators for RC modellers on the market. From the easiest available as freeware to sophisticated commercial products. Some commercial simulators, such as Phoenix require USB key supplied with the installation CD. These simulators do not need to deal with a connection problem, because the adapter is an integral part of supply.
There also exists simulators that allow connection of ordinary joystick, such as commercial ClearView or favorite freeware FMS. These simulators need to solve the problem of how to get the signal PPM/PPC from the transmitter to your PC and convert it to the value of the joystick deflections. There are basically two solutions, hardware and software one. On the Internet you can buy various USB adapters or can be found instructions for building such interfaces using PIC microprocessors. Both solutions have a major drawback, it takes a long time. Either waiting for the delivery service, or you take considerable effort on its own construction of such adapter.
I found a simpler option on the internet. It is a software called PPJoy. It picks up the PPM impulses from the parallel port and converts it to the joystick movements. Actually works as a joystick driver for RC transmitter. I used this solution a long time.
Nothing lasts forever. Upgrade PC brought the excellent performance, but also one trouble. The new PC is NOT! equipped with a parallel port. Parallel port simply gone forever. The first I thought that now is the purchase or construction of a USB adapter unavoidable. Nevertheless, I once again began to search for a smart software solution. And I was successful. I found a software converter of PPL pulses sensed from the input of sound card, which are then transmitted to PPJoy driver and next thing it works as before. Great!
All you need to do in hardware, is to get the connector for your transmitter and built in voltage adjustment for the sound card input (voltage divider). I took advantage of previously built PC oscilloscope.
Everything works perfectly in my ClearView simulator I have used it a few hours and I have not seen any problem. According to the authors of this solution, it would work in FMS without any problem. Simulator ClearView even declare support for this involvement on their sites.
ClearView simulator is not so good as above Phoenix or AFPD. But certainly it is a better solution than FMS. The ClearView price against competitors is one-third. The entire simulator controlled by your transmitter shots for $40+shipping. Phoenix costs $129+shipping, AFPD $179+shipping, RealFlight $200+shipping.