DCS in IP telephony communication standards

Could somebody tell me what does 开发者_如何学Cmean 'DCS' in IP telephony communication standards? I have looked at the internet and found that DCS is a distributed control system, but I think it's not relevant information when we talk about IP telephony communication standards.

A DCS is probably a Digital Cross Connect System in the context you have seen it, although it also seems to be a popular set of letters to include in product names, so check that it is not simply this you are seeing.

A digital cross connect is a 'box' or device that allows you switch between digital circuits - e.g. connect an incoming digital 'trunk' to an outgoing digital 'trunk' or phone 'line'.

You are correct that 'pure' IP telephony does not generally have to use cross connects as it is packet switched rather than circuit switched, but in the real world most IP telephony systems have to interface with or connect to older digital circuit networks and equipment.

For this reason you may see devices which act as a gateway between IP telephony networks and circuit switched digital networks - these boxes are often called Media Gateways.

See more about DSC at: http://en.wikipedia.org/wiki/Digital_cross_connect_system