I am using an SPA504G with a SIP provider. They support group call pickup and this has been configured through their web based GUI along with the BLF group.
I have been told the feature code for group pickup is *8 (they run an Asterisk server). This has been added to the attendant console settings in the Attendant Console Call Pickup Code field.
Sometimes the *8 works, other times it doesn't. I thought I had found that leaving it for a few rings allowed me to pick up the call but it later stopped working.
I have BLF working and use this in the extended functions field on a line key:
fnc=blf+cp+sd;sub=101xxxx@sip.xxxxxxx.net.au;ext=101xxxx;
I call in, BLF key lights up, I hit the button and the call drops on both ends. 1 out of 10 times it will answer though. The fact that it does answer sometimes tells me that the group pickup is configured correctly.
But then it gets really weird.... I call in on my mobile phone (CID enabled) when the call drops (after attempting the group call pickup) my mobile starts ringing.... If I answer it it just drops the call.
Not sure where to start looking. Phones are pretty much standard apart from some regional settings for ring sound and cadence.