Trunks

Trunks let you connect your FlyNumber phone system to external VoIP providers for both incoming and outgoing calls. This gives you control over call routing, which providers handle your calls, and how caller information is displayed.

important

This feature is not enabled by default. Contact FlyNumber support to request activation for your account.

Quick Start

Most users need trunks for one of these scenarios. Jump to the one that fits your needs:

I want to route all outbound calls through my own VoIP provider

Steps:

1. Go to Trunks > Termination Gateways and click +
2. Enter your provider's details (host, username, password, port)
3. Save the gateway
4. Go to Trunks > Termination Routes and click +
5. Create a route with:
   • Name: "All Outbound"
   • SRC Prefix: Leave empty
   • DST Prefix: Leave empty
   • Gateway: Select your new gateway
6. Save and test with a call

This catch-all route sends all outbound calls through your provider.

I want to route calls to specific countries through a different provider

Steps:

1. Create your termination gateway (if not already done)
2. Go to Trunks > Termination Routes and click +
3. Create a route with:
   • Name: "UK Calls" (or relevant country)
   • SRC Prefix: Leave empty
   • DST Prefix: "+44" (UK country code, adjust as needed)
   • Gateway: Select your gateway
4. Save and test with a call to that country

Calls to numbers starting with +44 will use your gateway; others use the default.

I want to receive calls from another VoIP provider on my FlyNumber system

Steps:

1. Go to Trunks > Inbound Trunks and click +
2. Note the auto-generated domain (e.g., xxxxxxx.in.phone.systems)
3. Configure your external provider to forward calls to this domain
4. If your provider requires registration, enable it and enter credentials
5. Test by calling from your external provider

Your FlyNumber system will receive calls sent to the trunk's domain.

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Overview

The Trunks interface has three sections:

Section	Purpose
Inbound Trunks	Receive calls from external VoIP providers
Termination Gateways	Define connections to outbound VoIP providers
Termination Routes	Control which gateway handles which outbound calls

Why Use Custom Trunks?

• Cost Control: Route calls through cheaper providers for specific destinations
• Provider Flexibility: Use multiple VoIP providers at once
• Number Portability: Keep numbers with other providers while using FlyNumber features
• Redundancy: Set up backup call paths
• Custom Routing: Route based on caller ID, destination, or both

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Inbound Trunks

Inbound trunks let you receive calls from external VoIP providers. Useful when you have phone numbers with other providers that you want to route through your FlyNumber system.

Creating an Inbound Trunk

1. Navigate to Trunks > Inbound Trunks
2. Click the + button
3. Configure settings:

Setting	Description
Domain	Auto-generated (e.g., xxxxxxx.in.phone.systems) — give this to your provider
Name	Friendly name (e.g., "External Provider Trunk")
Transport Protocol	UDP (most common) or TCP
Lookup Destination By	How to route calls (typically "R-URI username part")
Allowed Codecs	Audio formats to accept

Registration (If Required)

Some providers require your trunk to register with them:

1. Toggle Enable registration to ON
2. Enter:
   • Domain: Your provider's SIP domain
   • Port: Usually 5060
   • Username and Password: From your provider
   • Contact user: Optional identifier

CLI Rules

Modify caller information as calls arrive:

• Change caller names (e.g., add "External: " prefix)
• Reformat numbers (e.g., strip country codes)

Rules use POSIX Regular Expressions. See Understanding Regular Expressions below.

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Termination Gateways

Termination gateways connect your system to external providers for outbound calls.

Creating a Termination Gateway

1. Navigate to Trunks > Termination Gateways
2. Click the + button
3. Configure settings:

Setting	Description	Example
Name	Friendly name	"Main Provider"
Network Protocol	Usually IPv4 Only	IPv4 Only
Username	Auth username from provider	your_username
Password	Auth password from provider	•••••••
Host	Provider's SIP server	sip.provider.com
Port	Connection port	5060 (UDP/TCP) or 5061 (TLS)
Allowed Codecs	Audio formats	OPUS, G722, PCMU, etc.

Codec Selection

• OPUS: Highest quality, more bandwidth
• G722: HD voice quality
• PCMU/PCMA: Standard quality, widely supported
• G729: Lower bandwidth, slightly lower quality
• Always include telephone-event for DTMF tones

CLI Rules for Gateways

Rule	Purpose
SRC Rewrite	Modify outbound caller ID
DST Rewrite	Reformat destination number

Useful for adding/removing country codes or presenting specific caller IDs.

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Termination Routes

Routes determine which gateway handles each outbound call based on number patterns.

Key Point

Creating a gateway isn't enough—you must also create routes that tell the system when to use it. Without routes, calls use the default gateway.

Creating a Termination Route

1. Navigate to Trunks > Termination Routes
2. Click the + button
3. Configure settings:

Setting	Description
Name	Friendly name (e.g., "International Calls")
SRC Prefix	Match calls FROM numbers starting with this (optional)
DST Prefix	Match calls TO numbers starting with this (optional)
Gateway	Which gateway to use

Route Priority

More specific routes take precedence:

Priority	Configuration	Example
Highest	Both SRC and DST set	From +1555 to +44
Medium	Only DST set	To +44 (any source)
Lower	Only SRC set	From +1555 (any destination)
Lowest	Neither set	Catch-all

Tip: Longer prefixes beat shorter ones (+44207 beats +44).

Common Route Configurations

Route all calls through custom gateway:

• SRC Prefix: (empty)
• DST Prefix: (empty)
• Gateway: Your custom gateway

Route UK calls through custom gateway:

• SRC Prefix: (empty)
• DST Prefix: +44
• Gateway: Your UK provider

Route calls from specific DID:

• SRC Prefix: +15551234567
• DST Prefix: (empty)
• Gateway: Your custom gateway

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Troubleshooting

Problem	Likely Cause	Solution
Calls don't connect	Wrong gateway credentials	Verify username/password with provider
Registration fails	Network/firewall issue	Check connectivity to provider's server
One-way audio	Codec mismatch or firewall	Try different codecs; open RTP ports
Wrong caller ID	CLI rules needed	Add SRC Rewrite rule
Number format rejected	Provider expects different format	Add DST Rewrite to format numbers

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Reference

Understanding Regular Expressions

CLI rules use POSIX Regular Expressions:

Pattern	Meaning
^	Start of string
$	End of string
.	Any character
\d	Any digit
*	Zero or more of previous
+	One or more of previous
()	Capture group
\1	First captured group (in replacement)

Example: Add "+1" to 10-digit US numbers:

• Pattern: ^(\d{10})$
• Replacement: +1\1

Inbound Trunk Use Cases

Use Case	Description
Multi-Provider Integration	Route numbers from various providers to one system
Legacy Migration	Gradually move from old phone systems
Geographic Presence	Maintain local numbers from different regions
Redundancy	Backup call paths for reliability

Outbound Route Use Cases

Use Case	How to Configure
Cost Savings	Route by destination country to cheapest providers
Quality Control	Premium gateway for important calls
Local Presence	Present local caller IDs per region
Failover	Multiple routes to different gateways

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Getting Help

If you need assistance:

1. Open a support ticket with FlyNumber
2. Have your provider's documentation ready
3. Include (non-sensitive) details about your setup

tip

Some VoIP providers have specific FlyNumber integration guides—ask your provider if one is available.