15.5SP6: Codec priority in PBX settings?

[nobody]

There is a (for me) new setting in the PBX preferences:
Codec priority for Calls:
Default Values:
Internal/Local:
PCMU
PCMA
G722
GSM
G729
OPUS

External Calls:
GSM
G729
G722
PCMU
PCMA
OPUS

I can guess what internal call are, but "local"?
Also I guess most calls are External calls, but then the codec list does not make much sense IMO.
For my (living in Europe) and whishing to get audio like ISDN or better I would rather make the list this way:
Internal/local.
PCMA
PCMU
G729
G722
GSM
OPUS

External:
G729
PCMA
PCMU
G722
GSM
OPUS

Is that correct?
Why are the defaults for external calls prefer GSM?

Also There are the codec preferences for the trunks, and for the phones.
What will take precedence? Phone, trunk, or PBX?

Please explain.
Thanks

 

[cobaltit]

So there seems to be a line explaining that local/internal calls are as well as external calls so I'm not sure where the confusion lies. And it seems you have the ability to adjust the priority so just go ahead and make the adjustments as you see fit.

 

[nobody]

This feature in the PBX settings was not present in the SP5 version.
And why ist the GSM codec on top of the default list for external calls?
If the PBX settings has precedence over the phones or trunks that would mean that by default all outgoing call would use GSM codec if trunk and phone agrees. I find this confusing because I would not assume that this is a good default.