# Technical Capabilities

We provide detailed overview of the platform’s extensive technical capabilities, including support for various protocols such as SIP and RTP, as well as audio codecs.

### Protocols

|   Protocol   | Description                                                                                                                                                                                                     |
| :----------: | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
|      SIP     | SIP signaling, as specified in [IETF RFC 3261](https://datatracker.ietf.org/doc/html/rfc3261).                                                                                                                  |
|      TLS     | The Transport Layer Security (TLS) is a cryptographic protocol that provides secure communication over a network. Voice Gateway supports TLS 1.2 and later versions. TLS 1.3 is preferred for optimal security. |
| SIP over TLS | Partially encrypted SIP, as specified in [IETF RFC 3261](https://datatracker.ietf.org/doc/html/rfc3261). Some servers may communicate unencrypted, depending on specific requirements.                          |
|     SIPS     | Fully encrypted SIP, as specified in [IETF RFC 3261](https://datatracker.ietf.org/doc/html/rfc3261). All servers in the communication chain use TLS for encrypted communication.                                |
|      RTP     | The Real-time Transport Protocol as specified in [RFC 3550](https://datatracker.ietf.org/doc/html/rfc3550).                                                                                                     |
|     SRTP     | Encrypted media using the Secure Real-time Transport Protocol (SRTP), as specified in [RFC 3711](https://datatracker.ietf.org/doc/html/rfc3711).                                                                |
|     DTMF     | The use of RTP payloads to carry DMTF events, as specified in [RFC 2833](https://datatracker.ietf.org/doc/html/rfc2833).                                                                                        |
|   SIP REFER  | Sending the SIP REFER method to transfer calls, as specified in [RFC 3515](https://datatracker.ietf.org/doc/html/rfc3515). Receiving SIP REFER is not supported.                                                |

### Codecs

* `G.722` native.
* `G.711` 
* `G.729`
* `OPUS` (only SBC).

### Capabilities

Trunk management and Routing

* Transferring calls via [SIP REFER](https://datatracker.ietf.org/doc/html/rfc3515) or [SIP INVITE](https://datatracker.ietf.org/doc/html/rfc3261).
* Multiple SIP trunks per customer.
* Configuring SIP trunks with options like tech prefix, SIP Diversion header, Outbound authentication (including `REGISTER`).
* Routing calls based on a trunk group, Direct Inward Dialing (DID), or DID range.
* Least-cost routing selection of outbound trunk.

### Features

* Custom SIP headers on inbound and outbound calls.
* Mid-call SIP INFO requests.
* P-Asserted-Identity header to identify caller.
* Receiving compact SIP headers.
* Receiving re-INVITE with no Session Description Protocol (SDP).
* Configurable music on hold.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.conversational-ai.syntphony.com/user-guide/voice-gateway/technical-capabilities.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.