The desk handsets stop working when the internet is down. That is the simple, honest part of the answer. The important part is what happens to your inbound calls, and that is entirely under your control if the system is set up properly.
Standard fallback options
- Calls forward automatically to nominated mobile numbers when the desk phones do not register.
- Calls route to a mobile softphone app that continues to work over 4G or 5G, so nothing is missed.
- Calls divert to an out-of-hours message with a callback option and an SMS notification to a director.
- Calls fail over to a second site with staff who can pick up.
- Calls route to a dedicated answering service during declared incidents.
How the failover is triggered
A cloud phone platform notices when the endpoints (desk phones or apps) stop registering. That happens within a minute or so. At that point, your pre-configured failover rules kick in — no one needs to do anything manually.
This is a huge upgrade on legacy ISDN. When an ISDN line went down, calls hit a busy tone until an engineer showed up. Cloud telephony lets you decide, in advance, exactly what happens next.
How to build genuine resilience
- 4G or 5G failover router at the office so the internet itself never fully goes down.
- A second broadband line from a different carrier on a diverse route.
- Softphone apps installed on staff mobiles as a permanent backup.
- Regularly tested failover — most businesses set it up, then never test it.
- A written incident plan so everyone knows who does what within the first ten minutes.
Atom IP designs resilient call routing for every UK business we onboard — no extra cost, part of the migration.
Atom IP delivers Business Phone Systems across the UK. Book a free technology review and we’ll come back with practical, jargon-free findings.
