Emergency Number Forwarding (ENF) guarantees that inbound and outbound calls never drop, even if your customer’s site loses internet connectivity or power.
Instead of dead air, calls seamlessly redirect to preconfigured destinations—mobile phones, voicemail, IVR menus, call queues, and more—preserving business continuity and compliance with Kari’s Law and the RAY BAUM’s Act.
An independent ITIC survey of over 1,000 organizations found that the average cost of downtime now exceeds $300,000 per hour for over 90% of mid-sized and large enterprises. (ITIC)
So what is emergency number forwarding, and what does it mean for MSPs and IT providers? We will take a look at why ENF matters and how Viirtue PBX powers number forwarding, even during outages.
Why Cloud-Based ENF Matters
On-premises PBX gear often can’t detect when its SIP trunks or endpoints have gone dark. With Viirtue’s cloud-native approach to ENF:
Instant Failure Detection: Viirtue PBX continuously monitors SIP registrations from on-site devices.
Seamless Offline Mode: As soon as a device or trunk fails to register, calls are automatically routed according to your defined Offline Mode plan.
White-Label Customization: Resellers and service providers brand and configure every aspect of ENF via the Viirtue PBX portal.
Geo-Redundancy: Multiple data centers ensure the system stays online even if one region is impacted.
How Viirtue Cloud PBX Powers Emergency Number Forwarding
Continuous Registration Monitoring
Viirtue PBX tracks each SIP trunk and endpoint in real time. If a device stops registering—due to network outages, power loss, or hardware faults—the system immediately marks it “offline.”Preconfigured Offline Mode
You define one or more Offline Mode destinations in priority order. When a device or trunk goes offline, all calls bound for it instantly divert to the first available destination.Flexible Failover Destinations
Alternate Phone Number: Mobile DID or secondary office line
Voicemail Box: Ensures no messages are missed
Interactive Voice Response (IVR): Play custom announcements or menu prompts
Call Queue / Ring Group: Seamlessly shift calls to backup agents
Optional One-Click Manual Activation
While automatic rerouting is always armed, administrators can also force Offline Mode via a “Go Offline” button in the Viirtue hosted PBX portal—ideal for planned maintenance or testing.
Configuring ENF in the Viirtue Cloud PBX Portal
Log In
Go to your Viirtue PBX portal URL and authenticate as a reseller, admin, or end user.Access SIP Trunk Settings
In the left menu, click SIP Trunks, then select the trunk you wish to protect.Enable Offline Mode
Toggle Offline Mode on under Emergency Forwarding.
Enter your primary failover destination (e.g., mobile number, voicemail, IVR).
(Optional) Add secondary destinations in prioritized order.
Assign Manual Failover Permissions
Grant portal roles that can manually trigger Offline Mode for maintenance or drills.Test Your Failover
Use the built-in test harness to simulate registration loss and confirm calls route correctly to each configured destination.Monitor and Refine
Review daily health reports and event logs in the Analytics dashboard. Adjust your destination list and priorities based on call volumes and response performance.
Adjusting User Answering Rules in Viirtue PBX
To complement trunk-level failover, individual users can tailor their own Answering Rules:
Log In to Viirtue PBX
Navigate to your PBX portal URL and enter your extension and password.Open “Users” or “Extensions”
Select your user/extension profile.Edit “Answering Rules”
Business Hours: Define where calls ring during normal operations.
After Hours: Specify destinations for calls outside business hours.
No Answer: Set ring duration before redirecting (e.g., voicemail or secondary DID).
Busy: Route busy-line calls to a queue, colleague, or voicemail.
Configure “Offline” Rule
Under Trigger Conditions, select Device Offline.
Choose your desired destination: mobile DID, voicemail, IVR, or ring group.
Save and Validate
Click Save and, if available, use the test function to simulate offline scenarios and confirm your rules work as intended.
Admin Rerouting of Main Numbers from Inventory
Administrators can quickly reassign any DID from inventory—such as a company’s main number—to a new destination:
Log In to the Viirtue PBX Portal
Authenticate with your admin credentials.Navigate to Inventory → Main Numbers (DIDs)
Find the DID you want to reroute using search or filters.Edit the DID Assignment
Click the Edit icon next to the DID.
In Assigned To, choose:
SIP Trunk: Point to a backup or failover trunk.
User/Extension: Send calls to a specific employee or group.
Call Queue / Ring Group: Route to a team.
Voicemail or IVR: Catch calls in an automated flow.
Enable Offline Mode for the DID
Optionally toggle Offline Mode on and specify a secondary destination for that DID.Save and Notify
Click Save—changes take effect immediately. Inform impacted users via email or SMS.
Compliance Considerations for Emergency Number Forwarding
Implementing ENF is not only about reliability—it ensures you meet emergency-calling regulations:
Kari’s Law: Requires direct 911 dialing without prefixes. ENF must preserve this capability.
RAY BAUM’s Act: Mandates dispatchable location information. Viirtue PBX attaches accurate site addresses to forwarded 911 calls.
All failover events are logged with timestamps and call detail records (CDRs) for audit trails and regulatory reporting.
Best Practices for Reliable ENF
Monthly Failover Drills: Test your Offline Mode configurations regularly.
Diverse Destinations: Use at least two backup paths to account for mobile network outages.
CDR Auditing: Review call logs periodically to verify every forwarded call is captured.
How White-Label VoIP Resellers Use ENF as a Value-Add
Emergency Number Forwarding isn’t just a technical feature—it’s a powerful differentiator for white-label hosted VoIP resellers. With Viirtue PBX, partners can:
Offer guaranteed uptime as part of a high-availability SLA
Brand ENF features under their own logo and portal
Differentiate from agents or competitors who lack proactive failover tools
Command higher margins by promoting business continuity and regulatory compliance as bundled value
Whether you’re reselling to healthcare clinics, law offices, or multi-site enterprises, ENF gives you a competitive edge.
Conclusion
Emergency Number Forwarding (ENF) with Viirtue PBX ensures that calls detect registration failures in real time and instantly follow your Offline Mode plan—no complex rule builders, no dropped calls.
By combining trunk-level failover, user-level answering rules, and admin-controlled DID management—all managed in the Viirtue PBX portal—you deliver truly resilient voice services that keep your customers connected and compliant, whatever the emergency.
Emergency Number Forwarding (ENF) with Viirtue ensures that every call is accounted for—even in emergencies or outages. With built-in compliance, flexible configuration, and brandable options for white-label VoIP providers, ENF empowers you to deliver enterprise-grade reliability across your hosted VoIP services.
Want to learn more?
📞 Contact your Viirtue account manager or visit viirtue.com to get started with resilient VoIP solutions.
FAQ: Emergency Number Forwarding
What is Emergency Number Forwarding (ENF)?
ENF is a feature that detects when a phone system or SIP trunk goes offline and automatically routes calls to alternate destinations, ensuring no missed communication.
How does Viirtue detect an emergency routing condition?
Viirtue PBX monitors real-time SIP registration. If a device or trunk fails to register, it’s flagged as offline, and failover routes are triggered.
Can I customize ENF settings for each customer?
Yes. ENF can be configured per SIP trunk, user extension, or DID—and fully branded if you’re a white-label reseller.
Is manual failover available?
Yes. Admins can activate failover manually through the PBX portal for testing or planned maintenance.
Does ENF support mobile destinations or IVRs?
Absolutely. ENF supports routing to mobile numbers, voicemail, IVRs, ring groups, and more.
Does this help meet Kari’s Law and RAY BAUM’s Act requirements?
Yes. ENF preserves direct 911 access and appends accurate location data to calls, supporting compliance with both regulations.
