frequency test on phone lines

Is there any software available (preferably freeware) that allows you to test the frequency responses on a phone line?
There is a constant audible hiss / high pitched noise on my phone line and my telecom provider has utterly failed to fix it. There are no competing telecos in the area, so I can't switch provider. My teleco isn't contractually obliged to provide a line fit for data above 9600 baud unless I pay a VERY large sum of money for a digital line. Anyone got any thoughts?

Your right the telcom is not required to provide data capable above 9600 however, they are required to provide voice suitable lines, if you have an audiable hiss/high pitched noise during voice communications, this is what you need to tell them you want fixed... It should also fix the data transmission as a by product.... If you talk to them about data transmission they will give you every excuse in the book!!