Connecting my Philips PC headset to my Landline Phone

Inspired from my previous post,decided to make a connector that would link the traditional landline telephone to my Philips headset. To do this,I cut the telephone handset cable and used the 4 wires from it (black, red, green and yellow)to connect to a microphone socket black and yellow) and speaker socket (red and green). What it really enables is to not just connecting the phone to a headset, but also to my multimedia PC speakers for enabling a speaker phone with much better volume and fidelity. Reference: Ref 1 Ref 2