MODEM GETS A DIAL TONE AND HANGS UP 28.8 USR

on the 28.8 USR external modem, polling at 9600 baud rate the RPRO will initilize the modem and then it will get a dial tone and then hang up. changing the baud rate to a higher rate fixes the problem. 2400 and 4800 baud works in polling but doesnt work in dialouge. 9600 doesn’t work in either.