i have an SPA3102 with a PSTN line, 3cx server running on a dual 2.4ghz dual xeon server and a sipura spa-841 handset. when someone calls me on the pstn line they hear 4 rings before i hear one and asnwer. where is this delay coming from? can i fix it? i am finding a number of delays in the system that are somewhat discouraging otherwise i am happy with the product.