Asterisk pjsip sip tls

Not likely.
Yealink wanted me to do all their testing. Nope.
http://forum.yealink.com/forum/showthread.php?mode=linear&tid=41194&pid=#pid
Related thread I made here.

I also had problems with the S series until one of the more recent firmware versions (66.83.0.35 or 66.83.0.50).

The G series will likely never work.