Simple question about TTYs.. limits?

Hi! Ive installed Freeradius, its working great. I use it to verify users, im running a PPTPD server. I have a question though. When i do "radwho" it lists current users. The output is the following: userlogin username PPP S122 Tue 21:27 127.0.0.1 <givenIPadress> The question i have is, what does the S122 mean? I've never seen it go above S128, does this mean that the radius cant handle more then 128 current users? If so, how do i raise the limit? Or if the limit is not in the radius software, could it be a limit that is related to the OS (debian 2.4.27) or the PPTPD? Any help is very welcome! Thanks a bunch! :) Cheers! //Max