Hello, This might just be a general SIP question. I'm only barely getting in to this. I'm hooking some buttons and lights/buzzers up to some little Single Board Computers and having the computers register with asterisk and join a conference call. I want to be able to push a button on one board and have it beep/flash the other board ("Pick up the phone and pay attention"). What I'm trying to find out is the best SIP way (supported by pjsip) to go about this. It can't just be a call/ring because the other side will never pick up the call; It's already on the conference call. Should I just send an Instant Messages, or is there some other built-in SIP thing that already is for something like this? There's not a thing already in pjsua to run external scripts/programs on certain events, is there? I couldn't find anything. So I think I'll be using the python libs. Should be a pretty simple set of programs. thanks