control landline phone via smartphone app (VoIP device)

Hi, I've planed to control my landline phone via my smartphone app, I've trying to use ESP8266 as wifi bridge between mobile and telephone , regards to some searching I found , I should use DTMF decoder & generator IC as well as hang up, hang down , line splitter , ID caller and line status indicator circuit in my schematic , then use Audio to digital sampler with minimum latency to deliver mobile platform , I've decided to use TCP package to control land line and UDP package to deliver voice
any advise really appreciated