Why do I sometimes connect at a slower speed?
 
Phone line conditions can affect performance, as all 56K analog modem protocols rely on the existence of digital phone switches. If the local telephone company routes through an analog switch at any point on the connection from your home to the local node, you cannot exceed 33,600 throughput. If you have been using a 56K number and have an x2 modem, but have been unable to achieve 56K throughput, there may be a limitation on the phone line. A 36-44K throughput is average due to phone line conditions. Factors such as older copper cabling or the use of a splitter on the phone line reduces line quality. An excellent way to test your line is to use a utility available on U.S. Robotics Web page: http://modemupdate.usr.com56k/need4_56k/linetest.html

For more information on access numbers, go to Keyword: PHONES.