Gateways (SIP Trunks)

📖 Introduction

Gateways connect your PBX to the outside telephone network. They are SIP connections to VoIP providers, PSTN carriers, or other phone systems.

Without gateways you cannot:

Make outbound calls to external numbers
Receive inbound calls from the public phone network
Connect to other office locations

---

🎯 Common Use Cases

Scenario	Gateway Type
Outbound/inbound PSTN calling	VoIP provider (Twilio, Telnyx, etc.)
Connection to legacy PBX	SIP trunk to old system
Multi-site connection	SIP trunk between offices
Failover provider	Backup when primary fails

---

🖥️ Accessing the Module

Navigation: PBX → Routing → Gateways

---

📝 Form Fields

General Tab

Field	Description	Example
Name	Gateway identifier	`Twilio Production`
Gateway Type	Registration type	`Register`
Username	SIP authentication username	`+15551234567`
Password	SIP authentication password	`your-sip-password`
Realm/Domain	SIP domain	`sip.twilio.com`
Proxy	SIP proxy address	`sip.twilio.com`
Register	Send SIP REGISTER	`Yes`
Enabled	Gateway is active	`Yes`

Advanced Tab

Field	Description	Example
Codec Preference	Audio codecs to use	`G722, PCMU, PCMA`
DTMF Mode	How to send touch-tones	`RFC 2833`
Transport	SIP transport protocol	`UDP`
Ping Interval	Keep-alive frequency (sec)	`30`
Retry Seconds	Time between registration retries	`60`

Caller ID Tab

Field	Description	Example
Caller ID Name	Default outbound name	`Acme Corporation`
Caller ID Number	Default outbound number	`+15551234567`
Override Extension CID	Use this instead of extension CID	`No`

---

🚀 Practical Example: Adding Twilio Trunk

Scenario

Connect to Twilio for PSTN calling.

Step 1: Get Twilio SIP Credentials

From your Twilio console:

SIP Domain: yourcompany.sip.twilio.com
Username: Your Twilio phone number
Password: Your SIP credential password

Step 2: Create the Gateway

Field	Value
Name	`Twilio Production`
Type	`Register`
Username	`+15551234567`
Password	`(your password)`
Realm	`yourcompany.sip.twilio.com`
Proxy	`yourcompany.sip.twilio.com`
Register	`Yes`

Step 3: Test Registration

Check gateway status - should show "Registered"

Step 4: Create Routes

Create Inbound and Outbound routes to use this gateway.

---

💡 Tips & Best Practices

TIP

Test in sandbox first: Most providers have test environments.

TIP

Set up failover: Add a backup gateway in case primary fails.

TIP

Monitor registration: Gateways can lose registration due to network issues.

WARNING

Secure credentials: SIP passwords can rack up thousands in fraudulent calls if compromised.

---

Inbound Routes — Route incoming calls from gateways
Outbound Routes — Route outgoing calls through gateways

---

Next: Inbound Routes →