Audio visual cables and connectors in Perkins are offered by a number of manufacturers to media houses, movie production companies, ad agencies, telecom companies, computer hardware firms and others. They are used for carrying audio signal and video signal, of either analog or digital format. Shielded cables are used in analog A/V connectors to inhibit radio frequency interference (RFI) and noise. These cables and connectors have become popular over the years as they usually involve the simple plug and unplug process, instead of tightening of thumbscrews or other time-consuming procedures. Examples of audio visual cables and connectors are banana connectors, RCA connectors, Mini-VGA, and PAL connector.