I have the following enviroment:
I`ve a standard PBX in Mexico with 2 stations connected to fxo`s port on router. This router make a tunnel over Internet wirh ends into a callmanager in Brazil which is connected to another standard pbx with e1-qsig. This pbx has another e1 connected to another router wiht isdn signaling. This last router is connected with another router in USA via VPN. The router in USA is connected to an PBX via T1-ISDN. When a call is made form Mexico to USA, the call duration is exactly two minutes. All other calls working withouth problems, for example between USA and Brazil or Brazil and Mexico and vice-versa. Please, could you help me? Follow attached a simple drawing.