SIPHON logo

Outbound Trunks

Outbound Trunks

Outbound calls require an outbound SIP trunk (credentials for your SIP provider) so Siphon can dial the PSTN.

Provider-specific SIP examples (Twilio, Telnyx, Plivo, Wavix): Provider-specific quickstarts

SIPHON supports two approaches:

  • Provide full trunk credentials (sip_trunk_setup) so SIPHON can look up or create the trunk (recommended)
  • Or provide an existing outbound trunk ID (sip_trunk_id)

Recommended: use sip_trunk_setup

If you don’t already have a trunk id, pass credentials and SIPHON will reuse or create an outbound trunk.

from siphon.telephony.outbound import Call

call = Call(
    agent_name="Receptionist",
    sip_trunk_setup={
        "name": "telnyx-primary",
        "sip_address": "sip.telnyx.com",
        "sip_number": "+15550001",
        "sip_username": "...",
        "sip_password": "...",
    },
    number_to_call="+15550002",
)

SIPHON will:

  • Reuse an existing outbound trunk with matching settings, or
  • Create a new outbound trunk.

Use an existing outbound trunk ID

from siphon.telephony.outbound import Call

call = Call(
    agent_name="Receptionist",
    sip_trunk_id="ST_xxx",
    number_to_call_from="+15550001",
    number_to_call="+15550002",
)

If you omit number_to_call_from, SIPHON will attempt to infer it from the trunk.

Create an outbound trunk manually

If you want to create a trunk yourself (and then reference it by sip_trunk_id), you can use the trunk helper directly.

import asyncio
from siphon.telephony.outbound import Trunk

async def main():
    trunk = Trunk()
    result = await trunk.create_trunk(
        name="telnyx-primary",
        sip_address="sip.telnyx.com",
        sip_number="+15550001",
        sip_username="...",
        sip_password="...",
    )
    print(result)  # {"trunk_id": "ST_..."}

if __name__ == "__main__":
    asyncio.run(main())

Then pass the returned trunk_id into Call(..., sip_trunk_id=...).

Next