What values are you expecting to see to activate / deactivate the BLF’s

Ringotel works over the standard SIP/SIPS protocols and according to RFC3261 and SIP Events framework specifically. For concrete packet examples please refer to PBX documentation or some publicly available articles, for example:

• Asterisk Feature Busy Lamp Field (BLF) - Unify OpenScape Experts Wiki

• https://docs.skyswitch.com/en/articles/676-blf-and-mwi

• https://www.ietf.org/rfc/rfc4235.txt