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Set the Preferred Codec to G711u, set Use Pref Codec Only to yes.
Dial plans are tricky in the SPA3102. The following dial plan is an attempt to use 9 to dial through the PBX and no 9 to dial through an attached PSTN linewill dial just about any valid number (depending on you Dial Plan in the PBX) . Just before the end of the page set the Dial Plan to:(*xx|[3469]11|0|00|[2-9]xxxxxx|1xxx[2-9]xxxxxxS0|xxxxxxxxxxxx.)
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