B

Bot-to-Agent Handoff warm transfer, call transfer: Transferring a live call from the voicebot to a human agent, keeping the caller on the line. Supports warm, cold and whisper transfer.

D

DID Direct Inward Dialling, virtual number: A Direct Inward Dialling number – the phone number customers actually dial to reach your voicebot. Each DID can be routed to a different bot or flow.
DLT Distributed Ledger Technology: Distributed Ledger Technology registry – the TRAI-mandated system that records which businesses may send commercial messages and calls in India. VoiceLink scrubs 140-series numbers against it automatically.

K

KYC Know Your Customer: Know Your Customer – the identity verification required before telecom numbers can be activated for a business.

L

Latency: The delay between someone speaking and the voicebot responding. VoiceLink targets sub-200ms so conversations feel natural rather than stilted.

S

SIP Trunk Session Initiation Protocol trunk

What Is a SIP Trunk?

A SIP Trunk is a virtual communication connection that uses the Session Initiation Protocol (SIP) to connect a business’s phone system, PBX, Voice AI platform, or calling application to a telecommunications network over the internet.

Unlike traditional telephone lines, SIP trunks use an IP network to carry voice calls and other real-time communications. This allows businesses and Voice AI platforms to make and receive calls without requiring a separate physical phone line for every connection.

How Does SIP Trunking Work?

SIP trunking connects your communication system to a telecom or telephony provider through an IP-based connection.

A typical SIP calling setup works like this:

Voice Application / PBX → SIP Trunk → Telecom Network → Mobile or Landline

When an outbound call is initiated, the SIP trunk carries the signaling required to establish the call and enables voice traffic to be transmitted between the application and the telephone network.

For inbound calls, the process works in the opposite direction. Calls received through a business number can be routed through the SIP trunk to a PBX, contact center, Voice AI platform, or other connected application.

What Is the Difference Between SIP and SIP Trunk?

SIP is a communication protocol used to initiate, manage, and terminate real-time communication sessions.

A SIP trunk is the virtual connection that uses SIP to connect a communication system to a telephone network.

In simple terms:

SIP = the protocol
SIP Trunk = the connection
VoIP = the technology used to transmit voice over IP networks

Benefits of SIP Trunking

1. Scalable Calling Capacity

SIP trunks can support multiple simultaneous calls, making them suitable for businesses, contact centers, and Voice AI platforms that need to handle high call volumes.

2. IP-Based Connectivity

SIP trunks eliminate the need for individual physical telephone lines by using an IP network for communication.

3. Flexible Call Routing

Calls can be routed between different applications, numbers, PBX systems, agents, or Voice AI platforms based on business requirements.

4. Supports Voice AI Applications

SIP trunking can connect Voice AI platforms and voicebots to telecom networks, enabling AI applications to make and receive real-world phone calls.

5. Better Scalability for High-Volume Calling

Businesses can configure calling capacity based on their requirements, including concurrent calls and Calls Per Second (CPS).

6. Integration With Existing Communication Systems

SIP trunks can be integrated with IP-PBX systems, contact centers, communication platforms, and other SIP-compatible applications.

SIP Trunking for Voice AI

For Voice AI platforms, a SIP trunk can act as an important connectivity layer between the AI application and the telecom network.

For example:

Voice AI Platform → SIP/WebSocket → VoiceLink → Indian Telecom Network → Customer

This allows a Voice AI application to use telecom infrastructure for real-time inbound and outbound calling while the AI platform manages the conversation.

SIP-based connectivity can be particularly useful for AI voicebots, conversational AI platforms, contact centers, and enterprise calling applications that need scalable telephony infrastructure.

SIP Trunk vs Traditional Phone Lines

Feature	SIP Trunk	Traditional Phone Line
Connectivity	IP-based	Physical telephone network
Scalability	Highly scalable	Limited by physical lines
Multiple Calls	Supports concurrent calls	Typically requires additional lines
Integration	Works with IP-based systems	Limited integration
Voice AI Integration	Supported with compatible infrastructure	More complex
Infrastructure	Internet/IP network	Physical telephone infrastructure

What Are SIP Trunk Channels?

A SIP trunk channel represents the capacity to handle a concurrent call.

For example, if a SIP trunk has 100 channels, it can generally support up to 100 simultaneous calls, subject to the provider’s configuration and network capacity.

However, channels and CPS are not the same thing.

Channels determine how many calls can be active at the same time.
CPS (Calls Per Second) determines how quickly new calls can be initiated.

A Voice AI platform making large numbers of outbound calls needs to consider both.

SIP Trunking and Call Quality

SIP call quality depends on several factors, including network latency, jitter, packet loss, bandwidth, routing, and the audio codec being used.

Common codecs used in IP telephony include G.711 and G.729, while some modern communication applications may support other codecs depending on their infrastructure.

For real-time Voice AI, maintaining low latency and reliable audio transmission is particularly important because delays or packet loss can affect the quality of an AI-human conversation.

Is SIP Trunking Secure?

SIP trunking uses IP networks, so security should be considered when deploying SIP-based communication.

Depending on the architecture, security measures can include:

SIP authentication
Access control
IP whitelisting
Encryption
Secure signaling
Network monitoring
Fraud detection
Firewall and session border controller (SBC) protection

The exact security architecture depends on the SIP provider, application, network, and deployment model.

SIP Trunking vs SIP-to-SIP Calling

SIP-to-SIP calling allows communication between two SIP-enabled endpoints without necessarily connecting to the public telephone network.

SIP trunking, on the other hand, is commonly used to connect an IP communication system to a telecommunications network so it can make or receive calls to regular mobile or landline numbers.

Frequently Asked Questions