When using SIP

[Maxwell1001]

when using SIP G711 compression in the UK, should we be using ALAW or ULAW? the reason i ask is because i have been setting it up as ALAW and have just realised that when you request G711 with Voiceflex its ALWAYS ULAW unless requested using VCM channels for each call.

Im not fussed who is right or wrong just want to get it setup correctly on all our sites and not have the same issue in future..i thought we used alaw but im struggling to remember (shows how much i remember from my CTP2007)

thanks in advance

ACA - IP Office
ACS - IP Office

 

[Bas1234]

Normally it ALAW (ISDN/SIP for EMEA), but the when it's SIP the SIP server can be anywhere in the world so if the server is in the US than it could use ULAW.

If during call setup negotiation with a specific codec, connect fails, the IP Office will fallback to using automatic selection, so it will use G.729. It better to check how the call comes in and look for the codec they use select that in the IPO on the SIP Line if you don't want G729 but G711 ALAW/ULAW.

For incomming calls you could set "Use Offerer's Codec"

Use Offerer's Codec: Default = Off, Software level = 4.2+.
Normally for SIP calls, the answerer's codec preference is used. This option can be used to override that behaviour and use the codec preferences offered by the caller.

The more negotiations there need to be done the more traffic will go over the IPO/Gateway.

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It works! Now if only I could remember what I did...
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[Maxwell1001]

thanks..yeah i noticed that use offeres codec the other day...

so note i BEWARE when asking for G711 from Voiceflex specify what version of codec you want or they will automatically provide G711 ulaw

thanks..

ACA - IP Office
ACS - IP Office