Table of Contents
Overspend Safeguarding (OSG)
What is Overspend Safeguarding (OSG)?
OSG is a real-time spend-control feature designed for Pay Monthly mobile subscriptions. It allows Service Providers to set a maximum out-of-bundle (OOB) spend limit for each subscriber. Once this limit (called the OSG Cutoff) is reached, any additional OOB usage is automatically blocked. This helps prevent unexpected charges and ensures compliance with Ofcom’s bill-shock regulations.
How does OSG work in practice?
OSG operates through Transatel’s Online Charging System (OCS), which monitors subscriber usage in real time. When a subscriber uses services outside their bundle (e.g., extra data or roaming), these charges accumulate in the OSG “Charged” balance. If the Charged balance reaches the predefined Cutoff, OSG instantly blocks further OOB usage. This mechanism applies across national and roaming data, international calls, and SMS.
Which services are controlled by OSG and which are not?
- Controlled:
- National and roaming data (Zones 1–6)
- International voice and SMS
- Roaming voice and SMS
- Not controlled:
- National voice and SMS (managed offline, not in real time)
- Premium services in the UK (remain unlimited even after Cutoff)
- Premium services while roaming (blocked by default)
How is the OSG Cutoff calculated?
The Cutoff is based on wholesale tariffs, not retail. Service Providers must convert the subscriber’s requested retail bill limit into a wholesale equivalent by removing VAT and applying their markup.
Example:
Retail limit = £20
Remove VAT (20%): £20 ÷ 1.2 = £16.67
Remove markup (30%): £16.67 ÷ 1.3 = £12.82
OSG Cutoff = £12.82
Can subscribers still buy add-ons or roaming bundles when OSG is active?
Yes. If an add-on or roaming bundle is purchased, usage will first deduct from that bundle before impacting the OSG Charged balance. This means subscribers can continue to manage their usage without disabling OSG.
What happens when the OSG Cutoff is reached?
Once the Cutoff is reached:
- All OOB usage (data, roaming, international calls/SMS) is blocked.
- Premium services in the UK remain available and unlimited.
- Roaming premium services are blocked.
Subscribers receive an SMS notification informing them that their spend cap has been reached.
How can Service Providers manage OSG?
OSG can be managed via:
- Auriga Web Interface: Activate/deactivate OSG, set Cutoff values, view Charged balance, and adjust renewal dates.
- OCS-API & Webhooks: Automate OSG management and receive real-time notifications for events like activation, renewal, or reaching 80%/100% of the Cutoff.
Are subscribers notified about their OSG status?
Yes. Transatel sends SMS alerts at key thresholds:
- 80% of Cutoff: “You have used 80% of your mobile bill limit.”
- 100% of Cutoff: “Your mobile bill limit has been reached and services with additional charges are no longer available.”
MVNOs can also create custom notifications using webhook events.
Is OSG compatible with other options like Data Safeguarding (DSG)?
No. OSG and DSG cannot run together because OSG uses wholesale tariffs while DSG applies retail values. If OSG is active, DSG is ignored.
What happens if OSG is disabled?
Disabling OSG removes all spend protection. All OOB usage becomes unrestricted (“open bar”), which can lead to high bills if not monitored.
