Lotus Development Corp has lost interest in its Signal system, used to deliver share price quotations over FM radio sidebands, and is to sell the business to Infotechnology Inc for about $10m. The service has about 10,000 subscribers and is profitable. Lotus originally saw Signal as complementary to its 1-2-3 spreadsheet products, the idea being that users should feed the quotes straight into spreadsheets on their personal computers for applications such as revaluing portfolios and discerning trends.