voip gateway

i have a task from my bos to setting up voip gateway using 3 cx software for replace pbx/pabx and for adapter voip gateway (still looking) any suggest what adapter voip gateway must be i get that mean support to 3cx

1. how about Linksys PAP2T?

2. how about Linksys SPA3102?

3. or airlive 111A?

which one the correct adapter voip and how to setting it up?

any suggest for me please give a comment?