OneNET Voice Call Service (VCS) API
语音通话 (Voice Call Service) is China Mobile's publicly documented voice capability on the OneNET gateway, reached at https://openapi.heclouds.com/vcs?action={voiceNotify|dialNotify}&version=2. Click to dial (点击拨号) connects a caller and a callee across the China Mobile network; voice notification (语音通知) plays an approved TTS template to a subscriber and can collect DTMF digits. Both return a call_id and both deliver call-status callbacks to a caller-supplied notify_url, with documented status and disconnect-reason enumerations. Click to Dial is the domestic first-party product behind the CAMARA Click to Dial API that China Mobile sponsors upstream with Huawei — the shipped product does not implement the CAMARA schema or its OIDC/CIBA security model. Access is gated three ways — business entitlement, a test account pinned to an approved source IP, and a trial-usage quota. Service numbers and TTS templates require qualification review before use.