Modernize GR-303 Networks with TelcoBridges and Alianza

Solution Overview

According to the FCC’s Voice Telephone Services Report published May 16th 2025, there were 18 million subscribers with a TDM phone line as of June 2024 in the United States. At the same time, robocall enforcement mandates (STIR/SHAKEN) now apply to TDM networks, creating new compliance pressures on legacy switching environments. Manufacturers like Metaswitch (acquired by Alianza) have announced end-of-life for hardware platforms like the UMG, while many traditional Class 5 switches face discontinued support, spare parts scarcity, and increasing operational costs. The message is clear: service providers need flexible, modern voice infrastructure that aligns with today’s operational and regulatory demands. To support this shift, TelcoBridges and its alliance partner Alianza offer a straightforward solution that enables a smooth migration from TDM to IP with minimum service disruption.

Above: proposed modernized network with GR-303 infrastructure

Strategy

This joint solution integrates TelcoBridges’ Tmedia gateways with Alianza’s MetaSphere Call Feature Server (CFS), enabling providers to retire legacy Class 5 switches while preserving their existing GR-303 access infrastructure.

The Tmedia gateway connects directly to GR-303-based remote terminals, allowing providers to preserve their access lines. It converts GR-303 signaling to H.248 and hands it off to the software-based MetaSphere CFS. The softswitch handles SIP registration, subscriber services, and all call control functions.

This setup enables carriers to retire legacy Class 5 switches or end-of-life hardware like Metaswitch UMGs, without making big changes at the customer site. Tmedia platform also supports high availability configurations, keeping service running even in the event of a hardware failure.

6 Key Benefits of GR303 Solution

Preserves existing GR-303 access infrastructure without changes at the customer premises.
Replaces legacy Class 5 switches and UMGs with an interoperable solution.
Connects smoothly to the Alianza MetaSphere CFS softswitch.
Offers high availability options to keep services running without interruption.
Simplifies operations by centralizing control and reducing site visits with easy-tomanage infrastructure.
Cuts support costs with TelcoBridges’ 24/7 technical assistance, free replacements, and low maintenance

Conclusion

TelcoBridges and Alianza make it easier for service providers to bring legacy voice networks into the modern era. By bridging existing GR-303 access systems to a cloud based softswitch, providers can reduce costs, simplify operations, and roll out new services with minimum service disruption. Built on proven technology and real-world deployment experience, this solution supports a sustainable transition to IP-based voice. Combined with dramatically lower maintenance costs, this approach can reduce annual cost of ownership by up to 80% compared to legacy switch environments