 An alternative method of connecting VGA devices that maintains very high signal quality even over extended cable runs is the BNC connector, typically used as a group of five connectors, one each for Red, Green, Blue, Horizontal Sync, and Vertical Sync.With BNC, the coaxial wires are fully shielded end-to-end and through the interconnect so that no crosstalk or external interference is possible, easily doubling standard VGA's maximum reliable distance of 15 metres, and reaching 40–50 metres with the aid of nothing more than a simple signal booster.However, BNC connectors are relatively large compared to the 15-pin D-shell, and some attention is needed - vs the insertion of that single plug - to ensure each cable goes to the correct socket; although the core RGB lines are coloured appropriately, the sync wires can be various arbitrary colours (yellow, grey, white, black) and although standards do exist for these it is often unclear which is the correct arrangement at the point of connection and it can become a process of elimination.