Most DVI connector types – the exception being DVI-A – contain pins that pass digital video signals. These come in two varieties: single link and dual link. Single-link DVI employs a single 165 MHz transmitter that supports resolutions up to 1920 × 1200 at 60 Hz. Dual-link DVI adds six additional pins (located in the center of the connector) for a second transmitter increasing the bandwidth and supporting resolutions up to 2560 × 1600 at 60 Hz.[3][4] A connector with these additional pins is sometimes referred to as DVI-DL (dual link). Dual link should not be confused with dual display (also known as dual head), which is a configuration consisting of a single computer connected to two monitors, sometimes using a DMS-59 connector for two Single Link DVI connections.