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Both join ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["bridgeName: \"sip-bridge\""]},", so audio flows bidirectionally."]},{"$$mdtype":"Tag","name":"li","attributes":{},"children":[{"$$mdtype":"Tag","name":"code","attributes":{},"children":["transport: \"TCP\""]}," is required for the ElevenLabs SIP endpoint (at the time of writing)."]},{"$$mdtype":"Tag","name":"li","attributes":{},"children":["The mutual ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["onHangup"]}," handlers ensure that when either party hangs up, the other leg is also torn down."]}]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":3,"id":"shell-curl","__idx":8},"children":["Shell (curl)"]},{"$$mdtype":"Tag","name":"CodeBlock","attributes":{"data-language":"bash","header":{"controls":{"copy":{}}},"source":"#!/bin/bash\nset -e\n\n: \"${PROJECT_ID:?ERROR: PROJECT_ID is not set.}\"\n: \"${KEY_ID:?ERROR: KEY_ID is not set.}\"\n: \"${KEY_SECRET:?ERROR: KEY_SECRET is not set.}\"\n: \"${SERVICE_ID:?ERROR: SERVICE_ID is not set.}\"\n: \"${SINCH_NUMBER:?ERROR: SINCH_NUMBER is not set.}\"\n: \"${ELEVENLABS_SIP_URI:?ERROR: ELEVENLABS_SIP_URI is not set.}\"\n\nDIAL_TIMEOUT=\"${DIAL_TIMEOUT:-30}\"\nMAX_CALL_DURATION=\"${MAX_CALL_DURATION:-7200}\"\n\necho \"Patching service ${SERVICE_ID} for inbound -> ElevenLabs SIP ...\"\n\nRESPONSE=$(curl -s -w \"\\n%{http_code}\" \\\n -X PATCH \\\n -u \"${KEY_ID}:${KEY_SECRET}\" \\\n \"https://voice.api.sinch.com/v2/projects/${PROJECT_ID}/services/${SERVICE_ID}\" \\\n -H \"Content-Type: application/json\" \\\n -d @- < /dev/null && jq '.' || cat)\nelse\n echo \"ERROR: API returned HTTP ${HTTP_CODE}:\" >&2\n echo \"${HTTP_BODY}\" >&2\n exit 1\nfi\n","lang":"bash"},"children":[]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":3,"id":"python","__idx":9},"children":["Python"]},{"$$mdtype":"Tag","name":"CodeBlock","attributes":{"data-language":"python","header":{"controls":{"copy":{}}},"source":"# Requirements: pip install requests\nimport json\nimport os\nimport sys\n\nimport requests\n\n\ndef env(name, default=None):\n value = os.environ.get(name, default)\n if not value:\n print(f\"ERROR: {name} is not set. Run: export {name}=...\", file=sys.stderr)\n sys.exit(1)\n return value\n\n\nproject_id = env(\"PROJECT_ID\")\nkey_id = env(\"KEY_ID\")\nkey_secret = env(\"KEY_SECRET\")\nservice_id = env(\"SERVICE_ID\")\nsinch_number = env(\"SINCH_NUMBER\")\nelevenlabs_sip = env(\"ELEVENLABS_SIP_URI\")\ndial_timeout = int(env(\"DIAL_TIMEOUT\", \"30\"))\nmax_call_duration = int(env(\"MAX_CALL_DURATION\", \"7200\"))\n\nurl = f\"https://voice.api.sinch.com/v2/projects/{project_id}/services/{service_id}\"\n\npayload = {\n \"callBehavior\": {\n \"type\": \"STATIC\",\n \"static\": {\n \"callName\": \"caller\",\n \"commands\": [\n {\"command\": \"answer\"},\n {\"command\": \"bridgeCall\", \"bridgeName\": \"sip-bridge\"},\n {\n \"command\": \"dial\",\n \"callName\": \"sip-agent\",\n \"from\": {\"type\": \"PHONE\", \"phone\": {\"number\": sinch_number}},\n \"to\": {\n \"type\": \"SIP\",\n \"sip\": {\n \"endpoint\": elevenlabs_sip,\n \"transport\": \"TCP\",\n },\n },\n \"dialTimeoutDurationSeconds\": dial_timeout,\n \"maxCallDurationSeconds\": max_call_duration,\n \"events\": {\n \"onAnswer\": [\n {\"command\": \"bridgeCall\", \"bridgeName\": \"sip-bridge\"}\n ],\n \"onHangup\": [\n {\"command\": \"hangup\", \"callName\": \"caller\"}\n ],\n },\n },\n ],\n \"events\": {\n \"onHangup\": [\n {\"command\": \"hangup\", \"callName\": \"sip-agent\"}\n ]\n },\n },\n }\n}\n\nprint(f\"Patching service {service_id} for inbound -> ElevenLabs SIP ...\")\n\nresp = requests.patch(url, json=payload, auth=(key_id, key_secret))\nif resp.status_code == 200:\n print(f\"Service updated (HTTP {resp.status_code}):\")\n print(json.dumps(resp.json(), indent=2))\nelse:\n print(f\"ERROR: API returned HTTP {resp.status_code}:\", file=sys.stderr)\n print(resp.text, file=sys.stderr)\n sys.exit(1)\n","lang":"python"},"children":[]},{"$$mdtype":"Tag","name":"p","attributes":{},"children":["Once the PATCH succeeds, call your Sinch number from any phone. Sinch answers and bridges you to the ElevenLabs agent."]},{"$$mdtype":"Tag","name":"hr","attributes":{},"children":[]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":2,"id":"scenario-2-inbound-sip-to-elevenlabs-agent","__idx":10},"children":["Scenario 2: Inbound SIP to ElevenLabs agent"]},{"$$mdtype":"Tag","name":"p","attributes":{},"children":["An external SIP client (softphone, PBX, or another SIP trunk) calls your Sinch SIP endpoint. The SVAML is ",{"$$mdtype":"Tag","name":"strong","attributes":{},"children":["identical"]}," to Scenario 1; only the ingress path differs."]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":3,"id":"what-changes","__idx":11},"children":["What changes"]},{"$$mdtype":"Tag","name":"ul","attributes":{},"children":[{"$$mdtype":"Tag","name":"li","attributes":{},"children":["Instead of a PSTN phone number, the external caller targets your Sinch SIP URI. The exact URI depends on how your project's SIP trunk is configured; consult the Sinch dashboard under your Voice project's SIP settings."]},{"$$mdtype":"Tag","name":"li","attributes":{},"children":["The ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["PATCH /v2/projects/{projectId}/services/{serviceId}"]}," payload is the same as Scenario 1 (the static behavior handles whatever inbound call arrives, regardless of whether it came in over PSTN or SIP)."]}]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":3,"id":"setup-1","__idx":12},"children":["Setup"]},{"$$mdtype":"Tag","name":"p","attributes":{},"children":["Run the same PATCH from Scenario 1 (shell or Python). Then, from an external SIP client, dial your Sinch SIP URI. The call is answered, bridged, and the ElevenLabs agent greets the caller."]},{"$$mdtype":"Tag","name":"blockquote","attributes":{},"children":[{"$$mdtype":"Tag","name":"p","attributes":{},"children":["If you have both a phone number and a SIP trunk assigned to the same service, the same static behavior handles calls from either ingress. You do not need separate services unless you want different call flows for PSTN and SIP callers."]}]},{"$$mdtype":"Tag","name":"hr","attributes":{},"children":[]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":2,"id":"scenario-3-outbound-pstn-bridged-to-elevenlabs-agent","__idx":13},"children":["Scenario 3: Outbound PSTN, bridged to ElevenLabs agent"]},{"$$mdtype":"Tag","name":"p","attributes":{},"children":["Sinch dials a phone number. When the callee answers, the call is bridged to the ElevenLabs SIP agent. Use this for outbound campaigns, appointment reminders, or survey calls where the AI agent drives the conversation."]},{"$$mdtype":"Tag","name":"p","attributes":{},"children":["This uses ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["POST /v2/projects/{projectId}/calls"]},"."]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":3,"id":"the-svaml-1","__idx":14},"children":["The SVAML"]},{"$$mdtype":"Tag","name":"CodeBlock","attributes":{"data-language":"json","header":{"controls":{"copy":{}}},"source":"{\n \"commands\": [\n {\n \"command\": \"dial\",\n \"callName\": \"origin\",\n \"from\": { \"type\": \"PHONE\", \"phone\": { \"number\": \"\" } },\n \"to\": { \"type\": \"PHONE\", \"phone\": { \"number\": \"\" } },\n \"dialTimeoutDurationSeconds\": 30,\n \"maxCallDurationSeconds\": 180,\n \"events\": {\n \"onAnswer\": [\n { \"command\": \"bridgeCall\", \"bridgeName\": \"bridge\" },\n {\n \"command\": \"dial\",\n \"callName\": \"elevenlabs\",\n \"from\": { \"type\": \"PHONE\", \"phone\": { \"number\": \"\" } },\n \"to\": {\n \"type\": \"SIP\",\n \"sip\": {\n \"endpoint\": \"\",\n \"transport\": \"TCP\"\n }\n },\n \"events\": {\n \"onAnswer\": [\n { \"command\": \"bridgeCall\", \"bridgeName\": \"bridge\" }\n ]\n }\n }\n ],\n \"onHangup\": [\n { \"command\": \"hangup\", \"callName\": \"elevenlabs\" }\n ]\n }\n }\n ]\n}\n","lang":"json"},"children":[]},{"$$mdtype":"Tag","name":"p","attributes":{},"children":["Key points:"]},{"$$mdtype":"Tag","name":"ul","attributes":{},"children":[{"$$mdtype":"Tag","name":"li","attributes":{},"children":[{"$$mdtype":"Tag","name":"code","attributes":{},"children":["callName: \"origin\""]}," is the PSTN leg. ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["callName: \"elevenlabs\""]}," is the SIP leg. Both join ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["bridgeName: \"bridge\""]},"."]},{"$$mdtype":"Tag","name":"li","attributes":{},"children":["The ElevenLabs ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["dial"]}," fires only ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["onAnswer"]}," of the PSTN leg, so the agent is not invoked for unanswered calls."]},{"$$mdtype":"Tag","name":"li","attributes":{},"children":[{"$$mdtype":"Tag","name":"code","attributes":{},"children":["onHangup"]}," on the origin tears down the ElevenLabs leg when the callee hangs up."]}]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":3,"id":"shell-curl-1","__idx":15},"children":["Shell (curl)"]},{"$$mdtype":"Tag","name":"CodeBlock","attributes":{"data-language":"bash","header":{"controls":{"copy":{}}},"source":"#!/bin/bash\nset -e\n\n: \"${PROJECT_ID:?ERROR: PROJECT_ID is not set.}\"\n: \"${KEY_ID:?ERROR: KEY_ID is not set.}\"\n: \"${KEY_SECRET:?ERROR: KEY_SECRET is not set.}\"\n: \"${SINCH_NUMBER:?ERROR: SINCH_NUMBER is not set.}\"\n: \"${DESTINATION_NUMBER:?ERROR: DESTINATION_NUMBER is not set.}\"\n: \"${ELEVENLABS_SIP_URI:?ERROR: ELEVENLABS_SIP_URI is not set.}\"\n\nDIAL_TIMEOUT=\"${DIAL_TIMEOUT:-30}\"\nMAX_CALL_DURATION=\"${MAX_CALL_DURATION:-180}\"\n\necho \"Dialing ${DESTINATION_NUMBER}, will bridge to ElevenLabs SIP on answer ...\"\n\nRESPONSE=$(curl -s -w \"\\n%{http_code}\" \\\n -X POST \\\n -u \"${KEY_ID}:${KEY_SECRET}\" \\\n \"https://voice.api.sinch.com/v2/projects/${PROJECT_ID}/calls\" \\\n -H \"Content-Type: application/json\" \\\n -d @- < /dev/null && jq '.' || cat)\nelse\n echo \"ERROR: API returned HTTP ${HTTP_CODE}:\" >&2\n echo \"${HTTP_BODY}\" >&2\n exit 1\nfi\n","lang":"bash"},"children":[]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":3,"id":"python-1","__idx":16},"children":["Python"]},{"$$mdtype":"Tag","name":"CodeBlock","attributes":{"data-language":"python","header":{"controls":{"copy":{}}},"source":"# Requirements: pip install requests\nimport json\nimport os\nimport sys\n\nimport requests\n\n\ndef env(name, default=None):\n value = os.environ.get(name, default)\n if not value:\n print(f\"ERROR: {name} is not set. Run: export {name}=...\", file=sys.stderr)\n sys.exit(1)\n return value\n\n\nproject_id = env(\"PROJECT_ID\")\nkey_id = env(\"KEY_ID\")\nkey_secret = env(\"KEY_SECRET\")\nsinch_number = env(\"SINCH_NUMBER\")\ndestination_number = env(\"DESTINATION_NUMBER\")\nelevenlabs_sip = env(\"ELEVENLABS_SIP_URI\")\ndial_timeout = int(env(\"DIAL_TIMEOUT\", \"30\"))\nmax_call_duration = int(env(\"MAX_CALL_DURATION\", \"180\"))\n\nurl = f\"https://voice.api.sinch.com/v2/projects/{project_id}/calls\"\n\npayload = {\n \"commands\": [\n {\n \"command\": \"dial\",\n \"callName\": \"origin\",\n \"from\": {\"type\": \"PHONE\", \"phone\": {\"number\": sinch_number}},\n \"to\": {\"type\": \"PHONE\", \"phone\": {\"number\": destination_number}},\n \"dialTimeoutDurationSeconds\": dial_timeout,\n \"maxCallDurationSeconds\": max_call_duration,\n \"events\": {\n \"onAnswer\": [\n {\"command\": \"bridgeCall\", \"bridgeName\": \"bridge\"},\n {\n \"command\": \"dial\",\n \"callName\": \"elevenlabs\",\n \"from\": {\"type\": \"PHONE\", \"phone\": {\"number\": sinch_number}},\n \"to\": {\n \"type\": \"SIP\",\n \"sip\": {\n \"endpoint\": elevenlabs_sip,\n \"transport\": \"TCP\",\n },\n },\n \"events\": {\n \"onAnswer\": [\n {\"command\": \"bridgeCall\", \"bridgeName\": \"bridge\"}\n ]\n },\n },\n ],\n \"onHangup\": [\n {\"command\": \"hangup\", \"callName\": \"elevenlabs\"}\n ],\n },\n }\n ]\n}\n\nprint(f\"Dialing {destination_number}, will bridge to ElevenLabs SIP on answer ...\")\n\nresp = requests.post(url, json=payload, auth=(key_id, key_secret))\nif resp.status_code == 201:\n print(f\"Call created (HTTP {resp.status_code}):\")\n print(json.dumps(resp.json(), indent=2))\nelse:\n print(f\"ERROR: API returned HTTP {resp.status_code}:\", file=sys.stderr)\n print(resp.text, file=sys.stderr)\n sys.exit(1)\n","lang":"python"},"children":[]},{"$$mdtype":"Tag","name":"hr","attributes":{},"children":[]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":2,"id":"scenario-4-outbound-sip-bridged-to-elevenlabs-agent","__idx":17},"children":["Scenario 4: Outbound SIP, bridged to ElevenLabs agent"]},{"$$mdtype":"Tag","name":"p","attributes":{},"children":["Identical to Scenario 3, but the outbound leg dials an external SIP endpoint instead of a phone number. Use this when the person you are calling is reachable over SIP (a softphone, a PBX extension, another SIP trunk)."]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":3,"id":"the-svaml-2","__idx":18},"children":["The SVAML"]},{"$$mdtype":"Tag","name":"CodeBlock","attributes":{"data-language":"json","header":{"controls":{"copy":{}}},"source":"{\n \"commands\": [\n {\n \"command\": \"dial\",\n \"callName\": \"origin\",\n \"from\": { \"type\": \"PHONE\", \"phone\": { \"number\": \"\" } },\n \"to\": { \"type\": \"SIP\", \"sip\": { \"endpoint\": \"\" } },\n \"dialTimeoutDurationSeconds\": 30,\n \"maxCallDurationSeconds\": 180,\n \"events\": {\n \"onAnswer\": [\n { \"command\": \"bridgeCall\", \"bridgeName\": \"bridge\" },\n {\n \"command\": \"dial\",\n \"callName\": \"elevenlabs\",\n \"from\": { \"type\": \"PHONE\", \"phone\": { \"number\": \"\" } },\n \"to\": {\n \"type\": \"SIP\",\n \"sip\": {\n \"endpoint\": \"\",\n \"transport\": \"TCP\"\n }\n },\n \"events\": {\n \"onAnswer\": [\n { \"command\": \"bridgeCall\", \"bridgeName\": \"bridge\" }\n ]\n }\n }\n ],\n \"onHangup\": [\n { \"command\": \"hangup\", \"callName\": \"elevenlabs\" }\n ]\n }\n }\n ]\n}\n","lang":"json"},"children":[]},{"$$mdtype":"Tag","name":"p","attributes":{},"children":["The only difference from Scenario 3 is that ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["to"]}," on the origin leg uses ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["type: \"SIP\""]}," with a ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["sip.endpoint"]}," instead of ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["type: \"PHONE\""]},". Note that ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["transport"]}," is not set on the destination SIP leg here (it defaults to UDP), since the external SIP endpoint may support different transports than ElevenLabs. Set it explicitly if your destination requires TCP or TLS."]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":3,"id":"shell-curl-2","__idx":19},"children":["Shell (curl)"]},{"$$mdtype":"Tag","name":"CodeBlock","attributes":{"data-language":"bash","header":{"controls":{"copy":{}}},"source":"#!/bin/bash\nset -e\n\n: \"${PROJECT_ID:?ERROR: PROJECT_ID is not set.}\"\n: \"${KEY_ID:?ERROR: KEY_ID is not set.}\"\n: \"${KEY_SECRET:?ERROR: KEY_SECRET is not set.}\"\n: \"${SINCH_NUMBER:?ERROR: SINCH_NUMBER is not set.}\"\n: \"${DESTINATION_SIP:?ERROR: DESTINATION_SIP is not set.}\"\n: \"${ELEVENLABS_SIP_URI:?ERROR: ELEVENLABS_SIP_URI is not set.}\"\n\nDIAL_TIMEOUT=\"${DIAL_TIMEOUT:-30}\"\nMAX_CALL_DURATION=\"${MAX_CALL_DURATION:-180}\"\n\necho \"Dialing SIP ${DESTINATION_SIP}, will bridge to ElevenLabs SIP on answer ...\"\n\nRESPONSE=$(curl -s -w \"\\n%{http_code}\" \\\n -X POST \\\n -u \"${KEY_ID}:${KEY_SECRET}\" \\\n \"https://voice.api.sinch.com/v2/projects/${PROJECT_ID}/calls\" \\\n -H \"Content-Type: application/json\" \\\n -d @- < /dev/null && jq '.' || cat)\nelse\n echo \"ERROR: API returned HTTP ${HTTP_CODE}:\" >&2\n echo \"${HTTP_BODY}\" >&2\n exit 1\nfi\n","lang":"bash"},"children":[]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":3,"id":"python-2","__idx":20},"children":["Python"]},{"$$mdtype":"Tag","name":"CodeBlock","attributes":{"data-language":"python","header":{"controls":{"copy":{}}},"source":"# Requirements: pip install requests\nimport json\nimport os\nimport sys\n\nimport requests\n\n\ndef env(name, default=None):\n value = os.environ.get(name, default)\n if not value:\n print(f\"ERROR: {name} is not set. Run: export {name}=...\", file=sys.stderr)\n sys.exit(1)\n return value\n\n\nproject_id = env(\"PROJECT_ID\")\nkey_id = env(\"KEY_ID\")\nkey_secret = env(\"KEY_SECRET\")\nsinch_number = env(\"SINCH_NUMBER\")\ndestination_sip = env(\"DESTINATION_SIP\")\nelevenlabs_sip = env(\"ELEVENLABS_SIP_URI\")\ndial_timeout = int(env(\"DIAL_TIMEOUT\", \"30\"))\nmax_call_duration = int(env(\"MAX_CALL_DURATION\", \"180\"))\n\nurl = f\"https://voice.api.sinch.com/v2/projects/{project_id}/calls\"\n\npayload = {\n \"commands\": [\n {\n \"command\": \"dial\",\n \"callName\": \"origin\",\n \"from\": {\"type\": \"PHONE\", \"phone\": {\"number\": sinch_number}},\n \"to\": {\"type\": \"SIP\", \"sip\": {\"endpoint\": destination_sip}},\n \"dialTimeoutDurationSeconds\": dial_timeout,\n \"maxCallDurationSeconds\": max_call_duration,\n \"events\": {\n \"onAnswer\": [\n {\"command\": \"bridgeCall\", \"bridgeName\": \"bridge\"},\n {\n \"command\": \"dial\",\n \"callName\": \"elevenlabs\",\n \"from\": {\"type\": \"PHONE\", \"phone\": {\"number\": sinch_number}},\n \"to\": {\n \"type\": \"SIP\",\n \"sip\": {\n \"endpoint\": elevenlabs_sip,\n \"transport\": \"TCP\",\n },\n },\n \"events\": {\n \"onAnswer\": [\n {\"command\": \"bridgeCall\", \"bridgeName\": \"bridge\"}\n ]\n },\n },\n ],\n \"onHangup\": [\n {\"command\": \"hangup\", \"callName\": \"elevenlabs\"}\n ],\n },\n }\n ]\n}\n\nprint(f\"Dialing SIP {destination_sip}, will bridge to ElevenLabs SIP on answer ...\")\n\nresp = requests.post(url, json=payload, auth=(key_id, key_secret))\nif resp.status_code == 201:\n print(f\"Call created (HTTP {resp.status_code}):\")\n print(json.dumps(resp.json(), indent=2))\nelse:\n print(f\"ERROR: API returned HTTP {resp.status_code}:\", file=sys.stderr)\n print(resp.text, file=sys.stderr)\n sys.exit(1)\n","lang":"python"},"children":[]},{"$$mdtype":"Tag","name":"hr","attributes":{},"children":[]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":2,"id":"how-it-works","__idx":21},"children":["How it works"]},{"$$mdtype":"Tag","name":"p","attributes":{},"children":["All four scenarios use the same underlying mechanism: a ",{"$$mdtype":"Tag","name":"strong","attributes":{},"children":["bridge"]}," that joins two call legs."]},{"$$mdtype":"Tag","name":"ol","attributes":{},"children":[{"$$mdtype":"Tag","name":"li","attributes":{},"children":[{"$$mdtype":"Tag","name":"p","attributes":{},"children":[{"$$mdtype":"Tag","name":"strong","attributes":{},"children":["Inbound:"]}," Sinch receives the call on the service and executes the static SVAML. It answers the caller, puts the caller into a named bridge, then dials the ElevenLabs SIP endpoint as a second leg and puts it into the same bridge. Audio flows bidirectionally."]}]},{"$$mdtype":"Tag","name":"li","attributes":{},"children":[{"$$mdtype":"Tag","name":"p","attributes":{},"children":[{"$$mdtype":"Tag","name":"strong","attributes":{},"children":["Outbound:"]}," A ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["POST /v2/projects/{projectId}/calls"]}," creates the session. The first ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["dial"]}," reaches the destination (phone or SIP). On answer, SVAML puts that leg into a bridge and fires a second ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["dial"]}," to the ElevenLabs SIP endpoint, which also joins the bridge."]}]}]},{"$$mdtype":"Tag","name":"p","attributes":{},"children":["In both cases, the ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["bridgeCall"]}," command on each leg's ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["onAnswer"]}," is what connects the audio. The bridge name (",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["\"sip-bridge\""]}," or ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["\"bridge\""]}," in the examples) is arbitrary but must match across both legs within the same session."]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":3,"id":"sip-transport","__idx":22},"children":["SIP transport"]},{"$$mdtype":"Tag","name":"p","attributes":{},"children":["The ElevenLabs SIP endpoint requires ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["\"transport\": \"TCP\""]}," (at the time of writing). If omitted, the default is UDP, which may cause the SIP ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["INVITE"]}," to fail or audio to not flow. Verify the current transport requirement in the ElevenLabs documentation."]},{"$$mdtype":"Tag","name":"Heading","attributes":{"level":3,"id":"hangup-propagation","__idx":23},"children":["Hangup propagation"]},{"$$mdtype":"Tag","name":"p","attributes":{},"children":["Each scenario includes ",{"$$mdtype":"Tag","name":"code","attributes":{},"children":["onHangup"]}," handlers on both the caller/origin leg and the agent leg so that when either party disconnects, the other leg is torn down. 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