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No busy signal in some situations

jf
Advisor

No busy signal in some situations

Hi,

when I call external numbers from my Polycom SP IP 450 (FW 3.2.7) and the called party is busy the phone sometimes does not play the busy ringbacktone. Instead it just goes into idle state.

I've traced the SIP traffic and got the two message flows:

 

No busy tone:

- Invite from phone to PBX

- 100 Trying from PBX to phone

- 183 Session Progress from PBX to phone

- 486 Busy here from PBX to phone

 

Busy tone played:

- Invite from phone to PBX

- 100 Trying from PBX to phone

- 183 Session Progress from PBX to phone

- 180 Ringing from PBX to phone

- 486 Busy here from PBX to phone

 

It seems to depend on the called party (the PBX on the other side or the PSTN provider) if there is a 180 Ringing before the Busy here.

 

What does the phone expect from the PBX if I want it to play the busy tone? I think the phone should play the busy tone in every situation where it receives a 486 or am I wrong?

 

Thanks

 

Jan

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1 REPLY 1
SteffenBaierUK
Polycom Employee & Community Manager

Re: No busy signal in some situations

Hello JF,

 

only briefly looking at this we only play any call progress tone when we receive a 180.

 

The 183 is supposed to play the progress tone from the network.

 

If this needs further clarification you may want to raise a ticket via your Polycom reseller.

 

Best Regards

 

Steffen Baier

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The title Polycom Employee & Community Manager is a community setting and does not reflect my role. I am just a simple volunteer in the community like everybody else. My official "day" Job is 3rd Level support at Poly but I am unable to provide official support via the community.

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Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge. If you need immediate and/or official assistance please open a service ticket through your proper support channels.
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