Inbound works perfectly, outbound garbles customer audio. Telnyx confirmed PCMU. Vapi AI support confirmed it's a Vapi-side media ingestion issue on the Telnyx outbound path. Phone number ID: 68c6799a-9645-4e30-ab3d-7ac652f2b169 Broken outbound call: 019ced1e-78d9-733b-be4d-75817acb792e Garbled customer channel: https://storage.vapi.ai/019ced1e-78d9-733b-be4d-75817acb792e-1773504781927-9de844b2-2c5b-4d6b-bd50-24bd086694f7-mono.wav Working inbound call (same number, same codec): 019cecec-d0e3-7000-8aa8-ef6270633535

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Thanks for sharing the call IDs and recording that’s really helpful. Since inbound works fine with PCMU but outbound through Telnyx produces garbled audio, it points to an issue in the Vapi outbound media ingestion path rather than codec negotiation. It may be related to RTP handling or transcoding on the outbound leg. Are your outbound calls going directly through Telnyx SIP, or is there another trunk/provider in between? @Patryk