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Extend (Mobile UC)
Your Business Number on Any Mobile Device — No App Required
Extend brings your corporate phone number natively to any mobile device using eSIM technology. No app downloads, no softphone headaches — just carrier-grade voice quality through the phone's native dialer. Your employees make and receive calls from their business DID on personal or company devices, with full UC integration, call recording, compliance controls, and unified billing.
Key Benefits
What Is Extend?
Extend is a Mobile Unified Communications solution that turns any smartphone into a fully integrated business endpoint — without requiring a separate app. Using eSIM technology, your corporate phone number is provisioned directly onto the device's native dialer. Employees make and receive calls using their business DID with carrier-grade cellular voice quality, while the call is fully managed by your UC platform — including routing, recording, analytics, and compliance controls.
The Universal Endpoint
Traditional UC deployments require desk phones, desktop softphones, and mobile apps — each with different user experiences and management overhead. Extend replaces all of these with a single universal endpoint: the employee's mobile phone. Using their existing calling plan and existing call control, employees get one call history, one voicemail, and one consistent experience whether in the office or on the road. It's the simplest way to extend enterprise communications to every worker.
Deploy in Minutes with eSIM
Provisioning is effortless. An administrator enables Extend access through the UC portal, and a QR code is generated. The user scans the code on their iPhone or Android device, the eSIM is instantly installed, and they're making and receiving calls from their business number — all within minutes. No truck rolls, no hardware shipments, no app store downloads.
Built for Workers on the Move
Extend is purpose-built for mobile and frontline workers across every industry — retail and hospitality staff, field sales and engineering teams, healthcare professionals, logistics workers, legal and consulting firms, and management teams who are always between meetings. If your workforce isn't tethered to a desk, Extend ensures they're always reachable on a professional business number with full corporate compliance.
Compliance and Corporate Control
Every call through Extend is subject to corporate call recording, monitoring, and analytics — critical for industries with regulatory requirements like financial services, healthcare, and insurance. Texting from the business DID ensures compliance with corporate communication policies. IT maintains full visibility and control over mobile communications without touching the employee's personal line or data.
Eliminate Desk Phones and Cut Costs
Extend removes the need for desk phones, DECT/cordless systems, and associated LAN infrastructure — eliminating hardware procurement, maintenance, troubleshooting, and replacement cycles. Businesses consolidate onto a single provider bill for mobile and fixed-line services, simplifying procurement and reducing total cost of ownership by up to 40%. With predictable international roaming through Day Pass, there's no more 'bill shock' from employee travel.
Frequently Asked Questions
Do employees need to download an app?
No. Extend works through the phone's native dialer — there's no app to install, update, or troubleshoot. Once the eSIM is activated via QR code, calls are made and received natively.
Does Extend work with personal (BYOD) phones?
Yes. Extend installs as a second eSIM on the employee's personal device. Their personal number and data remain completely separate from the business line. The employee gets a dedicated corporate number without needing a second phone.
What about call quality — is this VoIP?
No. Unlike softphone apps that route calls over data/WiFi (often resulting in poor quality), Extend uses the cellular network's native voice service. This delivers true carrier-grade QoS — the same call quality as any regular phone call, with no dependency on internet bandwidth.
Can calls be recorded for compliance?
Yes. All calls through the Extend number are fully integrated with your UC platform's call recording, analytics, and monitoring capabilities — just like any other endpoint on your system.
What phones are compatible?
Extend works with any eSIM-compatible smartphone, including iPhone (XS and newer) and most modern Android devices (Samsung Galaxy S20+, Google Pixel 3a+, and others). The eSIM standard is supported by virtually all smartphones manufactured since 2020.
How does international roaming work?
Extend includes access to Day Pass, an add-on service that provides predictable, fixed-cost roaming across 128+ countries. Employees travel internationally without incurring surprise roaming charges — just activate Day Pass for the countries they're visiting.
Your Next Three Steps
Reach Out
Whether it's slow infrastructure or critical downtime, we're here to listen.
We Craft a Solution
After understanding your specific challenges, we provide a customized quote, often the same day.
Get Back to Business
With our solution in place, you can focus on what really matters: growing your business.
Trusted by Businesses Across California
"We really appreciate the professionalism and clear communication California Telecom brings as our managed service provider across network infrastructure, SecOps, and the rest of the backend."
Joe Fancher
Jack Nadel Inc.
"California Telecom customer service is a shining example of what every service provider should offer. Our IT Production Services division is fully dependent on the internet. We've been a California Telecom customer for at least 7 years, and I'm amazed with the support team and level of service."
Oscar Navarro
Sony Pictures
"Long-time customer of California Telecom here, and I can say from experience that these guys are the definition of responsive. I can call or email and within minutes, have a Tier 2 engineer on the line troubleshooting the issue."
Danny Rodriguez
Lanair Group
"California Telecom has demonstrated commitment over the years, providing excellent 24/7 support and services with their T1's, VoIP service, and co-location service. They are as much a part of our business as our customers are."
Hanns Schweis
Thermal Dynamics
"We use California Telecom hosted voice and internet. Very happy since we migrated from traditional carriers like Time Warner and AT&T. Always pass on the referrals if anyone is asking for an ISP."
Vitaliy Sklyar
Netpower
"Service has always been prompt and professional, and I am yet to have any downtime. Much better than Charter and AT&T, who I suffered with for years prior."
Atilla Banoczy
Lanair Group
"We really appreciate the professionalism and clear communication California Telecom brings as our managed service provider across network infrastructure, SecOps, and the rest of the backend."
Joe Fancher
Jack Nadel Inc.
"California Telecom customer service is a shining example of what every service provider should offer. Our IT Production Services division is fully dependent on the internet. We've been a California Telecom customer for at least 7 years, and I'm amazed with the support team and level of service."
Oscar Navarro
Sony Pictures
"Long-time customer of California Telecom here, and I can say from experience that these guys are the definition of responsive. I can call or email and within minutes, have a Tier 2 engineer on the line troubleshooting the issue."
Danny Rodriguez
Lanair Group
"California Telecom has demonstrated commitment over the years, providing excellent 24/7 support and services with their T1's, VoIP service, and co-location service. They are as much a part of our business as our customers are."
Hanns Schweis
Thermal Dynamics
"We use California Telecom hosted voice and internet. Very happy since we migrated from traditional carriers like Time Warner and AT&T. Always pass on the referrals if anyone is asking for an ISP."
Vitaliy Sklyar
Netpower
"Service has always been prompt and professional, and I am yet to have any downtime. Much better than Charter and AT&T, who I suffered with for years prior."
Atilla Banoczy
Lanair Group
Extend (Mobile UC) serving businesses across Southern California: Los Angeles · Orange County · Inland Empire · San Bernardino County · Riverside County · San Diego County · Ventura County · Nationwide