SIP Trunk

For: sites with a carrier SIP trunk (Tata, Airtel, Jio, Vodafone or similar) and no PBX.

  • The carrier locks the trunk to your circuit, so it cannot point at a cloud service directly.
  • A small PC or NUC on your LAN bridges it to AstraDial.

Values we will supply

Fields shown as <...> are issued by AstraDial. Credentials are sent separately, over a secure channel.

1. What gets connected

flowchart LR subgraph SITE["Your site"] direction TB TRUNK["Carrier SIP trunk<br/>handed off on your LAN"] NUC["Routing PC / NUC<br/>small always-on machine"] TRUNK --> NUC end subgraph CLOUD["AstraDial cloud"] direction TB AD["AstraDial<br/>call logs · recordings"] APP["AstraDial app<br/>any PC, any network"] AD --- APP end NUC ==>|" encrypted tunnel"| AD classDef site fill:#eef2ff,stroke:#4f46e5,stroke-width:1px,color:#1e1b4b classDef cloud fill:#ecfdf5,stroke:#059669,stroke-width:1px,color:#064e3b class TRUNK,NUC site class AD,APP cloud

Your phones become the AstraDial app, on any PC.

2. What you need to provide

Item Requirement
Routing machine Small always-on PC or NUC. Minimum 2 cores / 4 GB / 30 GB. A mini-PC is ideal.
Power UPS strongly recommended. If this machine is off, calls do not flow.
Network Wired ethernet on the same LAN as the carrier handoff. Do not use Wi-Fi.
Static LAN IP Reserve one for the machine so it does not change on reboot.
Remote access So we can set it up and support it without a site visit.
Carrier details The handoff details your carrier gave you, and the numbers on the trunk.
Firewall Outbound only. No inbound rules, no port forwarding.

3. How the work goes

  1. You supply the machine. Install it, cable it to the LAN, give it a reserved IP, and give us remote access. That is the whole of your side.
  2. We configure it. We install the routing software and the encrypted tunnel. Nothing on your existing network changes.
  3. The carrier link. We point the machine at your carrier handoff.
  4. Some carriers must whitelist the machine's address first. If so, we tell you exactly what to ask them for.
  5. Numbers. We route your trunk's numbers to the right people and teams. See Add a number.
  6. We test with you. Details in Testing.

4. What this gives you

  • Incoming calls on your existing numbers ring in AstraDial, on any PC
  • Outgoing calls go out over your own carrier trunk, showing your own number as the caller ID
  • Every call through AstraDial is logged and recorded

  • No desk phones or PBX hardware to buy

  • Simultaneous calls: capped by what your carrier provisioned on the trunk. Tell us the number.

5. Testing together

Have someone with a mobile phone ready. We run these with you:

  1. Incoming — call one of your numbers from a mobile. It should ring in AstraDial, with clear audio both ways.
  2. Outgoing — place a call from AstraDial to a mobile. It should show your own number as the caller ID.
  3. Capacity — two calls at once, if your trunk supports more than one.

6. Things worth knowing

The routing machine is a single point of failure

If it loses power or its network link, calls stop. This is why we ask for a UPS and a wired connection. We monitor it and alert on loss of contact, but the hardware is on your site.

Do not repurpose a busy office PC

It must be always-on and undisturbed. A PC someone shuts down at night, or reboots for Windows updates, will drop calls. A dedicated mini-PC costs little and removes the problem.

7. Before we schedule

  • Confirmation of the routing machine (model, or that you want a recommendation)
  • Your carrier's handoff details
  • Number of simultaneous calls your trunk supports
  • The list of numbers to route to AstraDial
  • Remote access to the routing machine
  • A preferred low-traffic window for the changeover

AstraDial — IT and Ops · cats@astradial.com