Industrial Leased Line Replacement

Seamlessly migrate legacy devices onto a modern Ethernet/IP or T1 network

For decades, leased lines have provided critical communications support for SCADA, teleprotection, radio and phones. Migration from leased lines is becoming more popular as companies in industries as utilities, public safety, and military and government seek to move to a modern network that offers easy legacy device integration, crucial redundancy and reliability, and the significant cost savings to meet budget requirements.

Migrate to a modern network and:

  • Extend the life of existing equipment
  • Eliminate recurring high expenses
  • Retain legacy devices

Replacement Solutions

Connect existing analog and other TDM interfaces over an IP/MPLS microwave or fiber network. Customers have the option to use an existing IP/Ethernet network, a carrier network or build one out.

The diagram showcases a typical network upgraded to IP/Ethernet using a JumboSwitch® TC3846-6 Analog & Dry Contact over IP/Ethernet gateway. Existing TDM devices (2-wire phones, 4-wire radios, serial RTU's, etc.) that were previously directly connected using leased services are kept in place while the network is changed to an Ethernet or MPLS network.

Another alternative to a copper leased line is a T1 line, offered as an option from some TELCOs. Replacing a leased service with a T1 connection comes with a different set of benefits than a packet-based connection. Primarily, a T1 connection bypasses prioritization requirements and cybersecurity maintenance and concerns. As a hardware-only product series, the Mini Channel Bank products have no firmware or require no configuration.

When transitioning off leased lines, users can expect extremely low latency and improved voice quality. The application diagram shows how one network was able to keep existing JPS SNV-12 Voters and Motorola Astrotac Receivers connected to 4W E&M Analog Radios and the TC8614 Analog & Dry Contact over T1/E1 Mini Channel Bank.

There are many variations on the basic leased line replacement solution. The process to replacing leased lines boils down to 2 basic questions:

  1. What is your old service type?
  2. What type of transport are you replacing it with?

In its most basic form, our leased line replacement solution involves moving from

Basic leased line replacement phone application

White Paper

Navigating Leased Line Network Modernization

Many carriers have been phasing out various leased line services for years, leaving critical industries challenged with replacement of existing devices due to cost, complexity, timing and more. This white paper explores common challenges and practical solutions to leased line retirement.

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Case Studies

Multi-county public safety agency upgrades microwave radio network

A public safety communications network in Iowa required a system-wide replacement to keep police, fire and emergency first responders connected. Reliability of equipment had degraded and vendor support was uncertain. Using a multi-service Ethernet platform, STARCOMM was able to improve audio quality and network management.

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ESRN eliminates leased line costs

East Shore Radio Network (ESRN) needed a replacement solution to eliminate their leased line costs. Support for leased lines had also lessened in recent years, so finding a cost-effective and future-proof solution was critical. Through deployment of the JumboSwitch TC3846-6, ESRN was able to fully integrate existing equipment while improving audio quality.

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Preserving essential legacy equipment with leased line replacement solution

Learning that telcos were beginning to phase out analog leased lines, a Northern California county needed to quickly find devices compatible with existing 4-wire analog radios, voters and P25 trunked radio systems – otherwise they faced increased costs and network downtime. Through the right solution, the county preserved legacy radio equipment while establishing a secure Ethernet backbone for critical radio communications.

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Public safety network minimizes communications disruptions by upgrading to T1

Facing disruption in critical communications when copper leased lines were planned to be discontinued, a town in New England utilized T1 and switched Ethernet services offered by the provider to keep emergency services in operation.

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Air Force tackles leased line retirement mandate in parallel with radio system upgrades

This airfield was mandated to upgrade its existing copper backbone to fiber, resulting in the need to upgrade their communications network. In addition, the airfield was performing an upgrade of their airfield radio system which needed to integrate with the proposed communications network solution. TC Communications assisted in migrating the entire communications network including communications between ground to air transmit receive (GATR), air traffic control (ATC) and the weather command post.

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"Over the past 35 years I have used similar boxes from other vendors for similar applications. But I have never seen one that would produce such a linear, uniform audio transmission from one end to the other - especially across an IP link."
- Martin T. Vinson, N.C.T., A.S.C.E.T.

Read the full review


Many Radio over IP (RoIP) solutions are SIP-based. SIP and VoIP can cause audio compression and have difficulty handling variation in latency. For a reliable and clear audio channel, particularly for critical communications, TDM over IP technology is a better alternative.

Clear uncompressed audio, passing tones and voter comparator compatibility can be achieved by using TDM over IP technology when designing a RoIP device for critical communications.

TDM over IP is a technology that emulates TDM over a packet switched network. TDM over IP takes a real-time bit stream and packetizes it. When combined with a special clock recovery scheme called Adaptive Clock Recovery* (ACR), this solution provides a low latency, reliable solution for clear analog audio and tones over an IP network.

As a result, TDM over IP-transported analog voice data is identical to a conventional telco's 600 ohm copper leased line. This technology has been used for many years to transport T1 or E1 over Ethernet.

*ACR is used to recover the clock by counting the bits in data stream which is extracted from packets received

TDM Based Radio Over IP

Reviews and Applications

Utility modernizes through easy migration of C37.94 edge solution onto MPLS

The JumboSwitch C37.94 IP Gateway passed a variety of latency and operating time tests for 87L Line Differential protection and was implemented as an easy edge solution on their MPLS network.

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Analog radio over IP: Enhanced audio with TDM-over-IP

For a reliable and clear audio channel particularly for critical communications, TDM over IP technology is a better alternative.

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