Key Takeaways:

SENTRY® Call Blocking blocks fraudulent calls before they reach consumers by authenticating outbound calls in real time, rather than flagging them as scam after the fact or even worse, the fraudulent call reaches your customer.

Every legitimate call gets a time-limited authentication key; calls without a valid key are blocked at the carrier network.

SENTRY works across all major U.S. carriers and integrates with existing phone systems via API or SIP, with no impact on legitimate call flow.

Full implementation takes roughly 6 to 8 weeks, since each carrier requires its own vetting, approval, and monitoring period.

What Is SENTRY Call Blocking and How Does It Protect Businesses From Spoofed Calls?

SENTRY is First Orion's call blocking solution that prevents scammers from using your business phone numbers to make fraudulent calls. When bad actors spoof your number, your customers receive calls that appear to come from your business — damaging trust and putting your brand reputation at risk. SENTRY stops this by authenticating every outbound call through a unique key system.

Before your call is placed, First Orion generates a time-limited key and shares it with the carrier network. When the call reaches the carrier, it checks that key — legitimate calls are delivered, and anything without a valid key is blocked before it ever reaches your customer.

SENTRY works across all major U.S. carriers and is especially critical for industries frequently targeted by impersonation fraud, including financial services, healthcare, and insurance.

How Does SENTRY Block Fraudulent Calls Made Using a Business Phone Number?

SENTRY integrates with your existing phone system through a simple API or SIP integration. When you initiate an outbound call, your system sends the caller and recipient details to First Orion. First Orion generates a unique authentication key with a time limit for that specific call and sends it to the mobile carrier.

When the call hits the carrier network, the carrier checks for a matching valid key. If it matches, the call goes through normally. If there's no key — meaning someone else is trying to use your number — the call is blocked and never reaches the recipient. The entire process happens in real time with no impact on your legitimate call flow.

What Businesses Benefit Most From SENTRY Call Blocking?

SENTRY is critical for industries targeted by impersonation fraud: financial services, healthcare, and insurance. If you handle sensitive customer data or operate high call volumes, your numbers are a target.

What Is Call Authentication and How Does It Work With SENTRY?

First Orion's Call Authentication is the advanced technology included in the delivery of SENTRY Call Blocking. Integrated into the network call flow, this feature verifies the caller and callee at the time the call is being made to confirm its legitimacy and determine if it should be blocked or reach the end user.

First Orion integrates with the business's calling platform to enable the ability to know when calls are being made by the business. First Orion's Digital Communication Exchange creates a unique key for each call to let the terminating carrier know the call is legitimate. These essential components authenticate calls in real time, blocking illegitimate calls and preventing them from being delivered to the end user.

How Long Does It Take for SENTRY to Become Active?

Call blocking is configured and monitored separately for each carrier. End-to-end implementation takes approximately 4-6 weeks (after successful integration with Call Authentication) depending on testing, approvals, and monitoring periods that comply with carrier agreements.

T-Mobile: SENTRY is implemented after telephone numbers are vetted and approved.

Verizon: SENTRY is implemented after the telephone numbers are vetted, approved, and have completed a 14-day blocking period on the T-Mobile network.

AT&T: SENTRY is implemented after the telephone numbers are vetted, approved, and completed a 14-day blocking period on the T-Mobile network.

Carrier requirements vary, and each carrier's monitoring period may last up to 21 days.

Start Spoof-Proofing Your Numbers Today

SENTRY Call Blocking is your non-negotiable insurance policy. It protects your brand, secures your numbers, and guarantees that your legitimate outreach can finally break through the digital noise. Don't wait until your number is hijacked. Secure your brand's identity.