agrsmsvc.exe is a Modem Service from Agere Systems belonging to Agere Soft Modem Call Progress Service .
This file is usually associated with the part of the audio device driver of the modem. It is a non essential process but is obviously required if the modem is to function properly.
Non-system processes like agrsmsvc.exe originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that over time your registry suffers fragmentation and accumulates invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues