If you can get one this is what you need:- http://www.dynalink.com.au/modems56k_dis.htm?prod=U90E-RURAL
Take care with USB external modems. There are some around which, while being external to the computer, use a windows program to do the conversion of the sounds to data bytes. They do not work under Linux. If you don't have a serial port there is a USB<=>RS232 serial converter which is available from DSE. for about $30. They work well with Linux. Cant tell you the DSE part number, the DSE site is down at the moment. I know of a source of a few ZyXEL 14,400 modems which will work excellently over absolutely crappy lines if that's a problem. -- Sincerely etc. Christopher Sawtell