Does Polycom VVX [BLF] send SIP Notify Messages to it's SIP Server First? or the Phone First?

[Anonymous]

Apologies if it's a silly question. But I'm using Asterisk 18.15.0 and I want to know for sure if Asterisk is sending SIP Notify Messages to Polycom VVX phones, or are the Phones them selves sending each other SIP Notify Messages

For Example:

I have to 2 Polycom VVX 500 SIP Phones. (Extension A and Extension B)
Both phones have a Line Key for BLF, and are listening to each other's Line.

I call the DID number for Extension A, with my cell phone. The following message appears on the Asterisk CLI:

Extension Changed <Extension A>[BLF] new state Ringing for Notify User <Extension B>

If Extension A answers the following message appears on the Asterisk CLI:

Extension Changed <Extension A>[BLF] new state Busy for Notify User <Extension B>

Does this mean that Extension A's Polycom VVX 500 phone, is sending SIP Notify Messages to the Asterisk Server, and then the Asterisk Server sends a SIP Notify Message to Extension B to tell it to change the status of Extension A?

OR  does the Phone itself send a SIP Notify Message to both the Asterisk Server AND the Other extension to let them know to change the status on the Extension?

I'm asking because recently, My Polycom VVX 500 Phone would say that another Extension is Busy, even when it is not on an active call. And I'm trying to find the culprit.

[SteffenBaierUK · Accepted solution]

Hello @wcafranklin ,

Welcome to the Poly Community.

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Unfortunately, your post fell a bit short of the above-explained requirements and we kindly ask you, therefore, to ensure to read these sections and ensure a reply (not Edit!) provides as much detail as possible

Please ensure you familiarise yourself with the FAQs listed in my signature for your convenience.

Nov 4, 2011 Question: How can I set up a Busy Lamp Field / BLF with a Digium Asterisk SIP Server?

Resolution: Please check => here <

Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.

Best Regards

Steffen Baier

[Anonymous]

Oh I see, so it is the Asterisk server that sends the response, I had overlooked that detail, I'm sorry.

I would still have to find out why the Phone still had a busy light, but I guess that isn't the Polycom's fault in this instance.