Im new to Elastix/Asterisk and have installed Elastix 1.5.2 over the weekend. I am having trouble with the Yeastar TDM400 analogue card, when I call a phone connected to one of the FXS ports on the card it will ring but when I pickup I can only hear noise. It's not just a little noise,it is load and I cannot hear anything. The noise can also be heard on the IP phone calling the extension. I also hear this noise when I pickup the phone connected to the FXS port to phone a number. The card shows up in hardware detection and displays what channels are FXO and FXS and which are in use. I have switched off echo cancellation to see if that will fix the problem but no luck. I also can't get the FXO line to work, at one stage when I phoned in it did answer with the same noise on the line but no phones rang or anything. I think if I can sort out the problem with the FXS extensions that I will have better luck with the FXO. Could this be a driver or configuration issue? They say on the website that the Yeastar TDM400 is fully compatible with the Digium TDM400 driver module wct4xxp.