also depends on another user(s) if you use xDSL and another user has 56k or 128k ISDN, user cannot "take" (you cannot send) files with high speed coz another user has LOUZY connection (slow) and is limited, and again if you with xDSL wanna take (recive) from that user something you cant recive files from him with high speed coz user has LOUZY (slow) connection

try:

/pdcc on
/dcc maxcps 0