I can see the advantades but have a lot to learn yet. I have 1 voip phone 1 tdm800 card [1 fxs 1 fxo], 1 linksys box. 2 fxs 1 grandstream ht488 1 fxs 1 fxo after instalation I have some probs. 1. fop is not working with 4 fxo ext of tdm zap channel it's showing them but can't drag to call, not red when busy... The error: "Unable to request channel ZAP/3" 2. I can't pickup calls by "*8" 3. I can't connect the grandstream ht488 to elastix ant idea?