Your 56k modem connects at 33.6k or less part

Some ISPs (Internet service Provider) put forth separate phone numbers for 56k. For example BSNL Net One gives one unique no. as the separate phone number through out Bharat. So, see that this type of separate phone number should be checked. Additional telephony devices (Landlines, Fax , Answering Machines) in a separate room , should be disconnected from the phone line .
Connect phone line from modem to the wall circuit.
Check for yours modem drivers updates. In recent version available then download and install . Always, make your system back-up before installing yours modem drivers.

Right click your dial up connection > property > Networking tab > “ Type of dial – up server I am calling” >setting > PPP Setting window > go to checkbox labelled “ Negotiate multilink for single link connection” . If the box is unchecked , check it and then uncheck Click on until the dialogue boxes vanish. If the box is checked remove the check mark and click ok until the dialogue boxes vanish.