Yes—as long as you enable failover routing for the line, calls to a regular geographic or national number will divert to the backup DID anytime the primary returns a busy tone, SIP error, or times out.
Scenario | What happens |
Primary DID connects | Call completes normally. |
Primary DID busy / unreachable / SIP 5xx | Carrier reroutes to failover DID within < 1 s. |
No failover DID set | Caller hears busy tone or fast-busy. |
Test | Method | Expected result |
Block primary PBX | Drop SIP traffic | Call diverts to failover DID |
Ring-timeout | Don’t answer primary | After timeout, backup rings |
Portal alert | Check Voice → Alerts | “Primary unreachable” logged; SMS/email sent |
Enable alerts so ops staff know whenever failover triggers.
Q: Can I add more than one failover DID?
A: Yes—set up cascading rules (primary → backup 1 → backup 2).
Q: Will callers notice extra ring delay?
A: No—diversion happens at carrier level in < 1 s.
Q: Do I need a different plan for failover?
A: Most business plans include one backup DID; additional routes may incur a small fee—check your contract.