the most common issue is related to the router’s ALG (Application Layer Gateway) settings. ALG can interfere with the SIP (Session Initiation Protocol) traffic required for BLF functionality. This happens because ALG tries to “translate” SIP packets, which can disrupt the smooth flow of information necessary for BLF updates, causing the lights to be unresponsive or greyed
features.blf.show_callinfo.enable=”1″
This is a feature that allows users to see who a busy BLF or parked call is with by holding down the BLF key. Tested on T41 and T48 (
That feature was only added in v84 )