ESC/P is a printer control language developed by Epson. The language was popular with dot-matrix printers. It uses escape codes, a command starts with the escape character. As an example, ESC E will switch on bold, and ESC F will switch it off. There are different versions of the protocol, which was also used by other printer manufacturers. Today, ESC/P is rarely used any more; modern printers use page description languages like Postscript, PCL or PDF.