The company sued the charity for more than £430,000 in the Court of Session in a dispute over payment for the provision of digital pens, which allow information to be entered automatically into a database using special pens and paper.
This-Tel is based in Dunblane, Perthshire, and has six members of staff and an annual turnover of about £750,000. It signed a three-year contract for the provision of digital pens with the disability charity in November 2009.
But the two sides ended up in court after the company said the charity had refused to pay it £284,800 for services and licences that it supplied, plus a further £153,674 in costs relating to a three-month notice period that the company said was written into the contract.
Leonard Cheshire Disability has more than 5,700 employees and had an income of £155m in 2010/11, according to figures on the Charity Commission website.
A Leonard Cheshire Disability spokeswoman said: "This matter has been settled out of court. The terms of the settlement are confidential and we have no further comment."
A spokesman for This-Tel said: "I am legally obliged to say absolutely nothing."