[asterisk-users] SPA504G auto answer

[Larry Moore]

On 23/10/2014 4:57 PM, Larry Moore wrote:
>
> On 23/10/2014 5:43 AM, Leandro Dardini wrote:
>> Hello,
>> I am struggling to have a SPA504G to auto answer (for intercom/paging).
>> I have tried the following SIP headers (not all together), but without
>> luck:
>>
>> SIPAddHeader(Call-Info:\;answer-after=0);
>> SIPAddHeader(Call-Info: answer-after=0);
>> SIPAddHeader(Alert-Info: info=intercom);
>> SIPAddHeader(Alert-Info: Ring Answer);
>> SIPAddHeader(P-Auto-Answer: normal);
>>
>
> What does your dialplan look like that makes the paging call?
>
> Listing from my Asterisk:
>
> '8000' => 1. Set(SIP_CODEC=alaw)
> 2. Dial(MulticastRTP/linksys/224.168.168.168:45678/224.168.168.168:6061)
> 3. Hangup()
>
>
> Using the Web Interface on you SPA501, log in as admin and select the
> advanced view. Select the SIP tab, down the bottom of the page there is
> a section headed 'Linksys Key System Parameters'.
>
> You will want settings much like
>
> Linksys Key System: yes
> Multicast Address: 224.168.168.168:6061
> Key System Auto Discovery: no
> Key System IP Address: <leave blank>
> Force LAN Codec: 711a <may be set to none, G711a or G711u>

For the benefit of others I encountered a situation where I was getting 
one-way audio in a call regardless of it not being a paging call, this 
was because the negotiated codecs for the call was one other than the 
one selected in the 'Force LAN Codec:' setting.

It would appear setting the 'Force LAN Codec:' to either G711u or G711a 
_always_ enforces the phone to use this codec for its Encoder regardless 
of what is negotiated in SIP.

My advice, leave the 'Force LAN Codec:' setting at its default value 
which is 'none'.

Larry.