walterbyrd writes: "On December 1, Microsoft will start charging enterprises a lot more money for some of its most popular software. By charging more for something it calls a "user client-access license," Microsoft is going to hit businesses where employees use its software on more than one device with a price hike. That's going to be painful for a lot of companies, thanks to the bring-your-own-device trend, where employees use their own tablets, laptops, or smartphones for work. Here's how it works: Whenever a business buys Microsoft software, such as SharePoint, it pays for two pieces. It pays for the software that runs on a computer server, and then it pays a fee for the number of "clients" that use that software. In this way, a company with 10,000 employees pays more for Microsoft software than a company with a 1,000 employees. Microsoft has two kinds of client access licenses, or CALs. One is a "device CAL" and it covers each device, no matter how many employees use that device. This is good for companies where one PC is shared by many employees, such as a PC in a nurse's station or a warehouse. The other is a "user CAL" and it covers each employee, no matter how many devices that employee uses. This is good for companies who want to let their employees access work files and emails from home computers, tablets, and smartphones. It used to be that device CALs and user CALs cost the same—making the user CAL a much smarter bet for bring-your-own-device workplaces. But on December 1, Microsoft will be increasing the prices for the user CAL by 15 percent, reports ZDNet's Mary Jo Foley."