SamyGO

It's ExLink port, not serial... 3,5 mm audio jack behind of the TV writes "Service" on it.
You can install SamyGO patched firmware to your TV IF you don't installed 2009 firmware before. IF you have 2009 version firmware, you cannot revert it back and you cannot install samygo patched firmware.
Also you needed to know your panel type if it's CI+ or CI. I cannot guess it since you don't write your FULL model number but half of it...

Thanks.

What is your Firmwares version number? If it's 2009, you don't needed to have ExLink too since you cannot do anything with that firmware.
Also you can build that cable from old headphones... Schematics available on wiki...

t-rror wrote:The version of firmware is CHL5DEUC-T-1010.0. Is it the right one? I will see the wiki to build the exlink cable.

It's old and look ok

Nope, Networking is not eabled in B550 kernel. Since you are on CI you can change model number for getting Wiselink Movie Playback, or just enable it manually via service menu... (see wiki).