See The Data Behind AT&T, Verizon, and Other TDM Turndown Case Studies

Major carriers across the globe are executing their TDM turndown strategies at varying paces, creating a complex landscape for enterprises and service providers to navigate. This comprehensive overview examines why do it, announced timelines, completed migrations, and lessons learned from carrier implementations worldwide. Here are the latest TDM Turndown Case Studies as of December 1, 2024.

The Turndown Motivation – Infrastructure Support Challenges

According to Rob Jodrie, Director of Technical Support at Syncworks, network operators face mounting pressure to migrate from TDM due to critical support challenges. “Much of the TDM network is comprised of systems that were manufacturer discontinued (MD) years ago,” explains Jodrie. “Operators are forced to procure parts from the ‘gray market’ in an attempt to keep this equipment limping along.”

Additional Key Concerns Include:

• Discontinued equipment with limited replacement parts
• Unreliable gray market components at premium prices
• Excessive power consumption compared to modern systems
• Limited alarm surveillance capabilities
• Critical services dependencies (E-911, SS7 call processing)

This industry insight directly aligns with the following carrier migration timelines. Aging infrastructure increasingly impacts network reliability and operational costs. These negative draws will continue to deepen with time.

TDM Turndown Case Studies

AT&T Network Evolution

AT&T’s TDM turndown represents one of the industry’s most ambitious transitions. The carrier has filed to decommission TDM services across multiple states¹:

• California: 13,000 business customers migrated by Q3 2023
• Texas: 15,000 TDM circuits decommissioned as of Q4 2023
• Florida: Migration completion scheduled for Q4 2024
• Expected completion of nationwide TDM turndown: 2026²

Verizon’s Migration Strategy

Verizon’s approach emphasizes customer communication and phased implementation:

• Completed migration of 150,000 business customers across six states³
• Northeast corridor migration: 89% complete as of Q1 2024
• Projected completion date for copper retirement: 2025⁴
• Investment in fiber infrastructure: $4.5 billion allocated⁵

CenturyLink/Lumen Technologies

Following their merger and rebranding, Lumen has accelerated their TDM turndown:

• 18 states completed TDM-to-IP transition
• 1.2 million voice lines migrated⁶
• Rural market strategy includes fixed wireless alternatives
• Target completion date: 2027⁷

International Carrier Implementations

British Telecom (BT)

• Digital Voice transition affecting 29 million lines
• £12 billion fiber investment program
• Complete PSTN switch-off by December 2025⁸

Deutsche Telekom

• IP migration completed in 2019
• 20 million customers transitioned
• Three-year implementation timeline⁹

Implementation Challenges and Solutions

AT&T’s Approach

• Dedicated migration teams by region
• Customer communication 24 months before transition
• Specialized support for critical infrastructure customers
• Regular FCC filing updates on progress¹⁰

Verizon’s Methodology

• Proactive circuit auditing
• Customer premise equipment assessment
• Security system verification process
• Emergency services coordination¹¹

Lessons Learned from Completed Migrations

1. Pre-Migration Assessment
   • Average discovery of 23% more active circuits than initially documented
   • Critical timing dependencies often overlooked
   • Security systems frequently overlooked in initial assessments
2. Customer Communication
   • 24-month notice proven most effective
   • Regular status updates reduce support calls
   • Dedicated support teams improve customer satisfaction
3. Implementation Timing
   • Average migration timeline: 18-36 months
   • Critical infrastructure requiring additional 6-12 months
   • Weather considerations for outdoor equipment replacement

References

For detailed migration planning guidance, refer to our Network Migration Planning Guide, and for business impact analysis, see our Enterprise Impact & Implementation Case Studies.

About Us Syncworks

For over twenty years, Syncworks has been evaluating, testing, designing, and implementing timing networks for telecom, cable, utility, and enterprise customers in the US and the Caribbean. We are a well-known and trusted partner and critical supplier to major network operators. As a diamond partner to Microchip and a skilled integrator of other vendor products, we can provide options for the most performant, resilient, and economical timing network possible. We specialize in ensuring that critical networks can survive disruptions like GPS jamming and spoofing. And we provide expert support, sparing, and repairs for everything we install leveraging the largest inventory of related products and components in the industry. 

Syncworks is a value-added stocking reseller of network sync and timing equipment for critical infrastructure companies. SyncCare and Field Services ensure your network equipment is flawlessly executed and supported.  

Our 10,000 sq. ft. warehouse stocks and ships critical equipment and replacements for networks all across the USA and the Caribbean. With expertise from GPS signal to our new output expansion panels, we an experience and trusted guide. Our tight-knit crew of engineers and field services technicians work together to efficiently and effectively bring your network to Stratum 1 standards.

Syncworks delivers the highest level of expertise to every project and offers a complete menu of network synchronization products and services. Our flagship product, the TimeProvider® 4100, is a gateway clock that accepts multiple inputs from Global Navigation Satellite Systems (GNSS), Synchronous Ethernet (SynE), and 1588 PTP Grandmaster Clock and E1/T1 digital transmission links.  

As a Microchip Diamond Partner, we maintain the largest and most diversified stocking supply of Microchip network sync & timing products to meet our customers’ every need when it comes to sync and timing technology.  

For more information, contact sales@syncworks.com or call (904) 280-1234