Busy Lamp

I would like to know if Asterisk can provide to IP-phone information about status of another IP-phone. It means: can one IP-phone have a key, programmed as supervision of another IP-phone (free, busy, ringing) ?

Artur Kalbarczyk

yes it can. This is supported in SIP via SUBSCRIBE/NOTIFY. to make asterisk work you must configure a few params including the hint extensions (IE to make extension 1234 monitor SIP/1234, do exten => 1234,hint,SIP/1234). You must also set subscribecontexts and subscribegroups (to grant access).

What kind of vendor (Cisco, Ericsson, etc.) You test this feature ?

voip-info.org/wiki-Asterisk+ … extensions has more info, but possibly not what you’re looking for.
It’s a standard part of the SIP protocol, so any phone that supports SIP BLF should work.
It has been successfully tested with (off the top of my head), Grandstream GXP2000 (with new firmware 1.0.13 available on the wiki); any SNOM products (they were the first, kudos to them), Aastra 9133i/480i/480i-CT, Sipura/Linksys SPA-841/SPA-941, and I think Polycom and Cisco.

Keep in mind, that the BLF only provides INFORMATION about the other phone. If somebodys phone is ringing, and you push the button on the phone next to the flashing light, it doesn’t answer the call. You must configure pickupgroups and dial *8 to answer the call.

Thank You for advice and suggestions !

no problem.

also one other thought- the ericsson phones you were asking about in another thread probably aren’t the best choice for * unless you already have them. I bring this up here because I’m not sure if Asterisk H.323 supports BLF at all. Everything i’ve said so far has been about SIP, and SIP phones are by far the most common. If you haven’t already invested in hardware, take a look at the brands and models I mentioned. If you are doing a large deployment, buy 1-2 of the phones first to get a feel for them and learn their ins and outs.

Good luck!