Asterisk Lagging


I just want to ask if there is any other setting in the asterisk and in the digium card that I have to change or consider to minimize the lag/delay of the voice.

My current set-up is I have an asterisk box located in the Philippines with a digium card in it. One of the E1 port is connected to LA via a fiber optic transmission using ISDN signalling. The quality of the voice clear but the delay is a little bit long. The card that I am using is TE140P.