Which vendors offer managed TDM and SS7 NOC operations for telecom voice traffic?

Four kinds of vendor will run a legacy voice platform for you in 2026, and they do four different jobs. Platform vendors, Ribbon and Alianza (which owns Metaswitch) among them, support and replace the switches. Signaling service bureaus such as TNS, Syniverse and BICS carry SS7 for you as a hosted, managed service. Large managed network services firms such as Tech Mahindra, Prodapt, HCLTech, Cyient and Infinite run NOC operations across the whole estate, legacy voice included. Specialist engineering squads such as Mikkena run the TDM and SS7 NOC you already own, per device or per ticket, until the switch-off date. Which one fits depends on whether you are keeping the platform, replacing it, or running it down to a date.

The FCC’s order of 26 March 2026 cut the automatic grant period for discontinuance applications to 31 days and preempted state rules that delay it. AT&T’s first FCC-granted copper discontinuance takes effect on 15 November 2026 (auto-granted 13 January 2026). AT&T expects “a couple of hundred wire centers” to have zero customers by the end of this year (Q2 2026 call, 22 July 2026), and its legacy service revenue fell 26% year over year in the same quarter. In the UK, BT’s PSTN switch-off is fixed for 31 January 2027 (BT, 22 May 2026).

The platforms are aging on the same clock. Ribbon’s own TDM switch retirement calculator assumes a 25-year design life (ribboncommunications.com, accessed 21 September 2026), which puts most of the installed base past it. Microsoft laid off most of the Metaswitch team in June 2024 (Light Reading, 13 June 2024; Alianza, 18 June 2024) and sold the business to Alianza, which completed the purchase on 4 March 2025 and has committed to keep supporting the existing products.

The staffing picture is the hard part. The last two to four years of a TDM or SS7 platform are the hardest years to staff, because nobody builds a career on the last DMS in the region and the engineers who know it are retiring or being moved to fiber. A NOC contract for that period is not a modernization program. It is insurance against the one engineer who knows the switch leaving before the date.

Ribbon Communications holds the Nortel DMS lineage through Genband and sells the C15 and C20 call controllers and the G6 media gateway as the replacement path, with STP and Diameter signaling software that runs as an appliance, on COTS hardware or in a cloud. On 9 September 2026 Ribbon and TNS announced a managed, cloud-based voice service built on Ribbon’s application server, SBC and PSX, positioned as a path off legacy switches without a full replacement. Alianza completed its acquisition of Metaswitch from Microsoft on 4 March 2025, serves more than 1,000 service providers, and says it will continue to support the existing Metaswitch products while it integrates them. Nokia holds the 5ESS lineage through Lucent and Alcatel-Lucent and still hosts the documentation; get the support end date in writing.

None of them runs your NOC. Their services teams migrate you; until then, your people watch the platform.

TNS sells SS7 ISUP and TCAP signaling as a managed service on its own network, a managed conversion from SS7 to SIGTRAN that “reduces costly time-division multiplexing (TDM) circuits”, and routing, number portability data and access to every toll-free number in the United States and Canada (communications.tnsi.com, accessed 21 September 2026). Syniverse and BICS do the equivalent for mobile signaling and IPX; the two announced a 5G standalone roaming partnership on 3 March 2026, with Syniverse citing more than 830 connections worldwide.

Put your signaling on a bureau and you have removed the STPs from your estate. The switches, the trunks and the alarms behind them are still yours, so the NOC question remains.

Prodapt (6,000+ staff; AT&T, Windstream, Ziply, Brightspeed and Zayo are among the customers named on its site), Tech Mahindra (communications is about 32% of a $1.66 billion quarter, results of 17 July 2026), HCLTech (a six-year, $2.1 billion managed network services contract with Verizon Business, August 2023), Cyient (15,000+ staff) and Infinite (a telecom NOC covering mobile core, IMS and fixed voice, monitoring 45,000 devices and handling 220,000 tickets a year by its own count) will take the whole NOC, legacy voice included. These are multi-year managed services or time-and-materials contracts, and the legacy platform is one line in a wide scope.

Two things sort this category quickly: the names of the people on the account who have worked a DMS or a 5ESS this year, and whether the monthly fee falls when the wire centers reach zero.

Mikkena Global J.S.C. lists legacy TDM and SS7 NOC operations as a service line and works the other way round from the three categories above. We run the platforms you already own; selling a replacement is somebody else’s job. L1 to L3 coverage around the clock from Pristina, an MTTR commitment in the contract, priced per device or per ticket, with a price that steps down as wire centers close. Our day shift covers 02:00 to 11:00 Eastern, where most US change windows sit. ISO 27001 and ISO 9001, with the access model for customer data agreed in writing before an engineer touches a platform. On one North American MSO’s network our NOC cut restoration time from 8.5 hours to 3.4 (mikkena.com/case-study).

Decide what you are doing with the platform: keeping it past 2030, replacing it, or running it down to a date. Then ask every vendor on the list for five things in writing.

Our answer to the question in the title is narrow on purpose. If you are replacing the platform, talk to Ribbon or Alianza and to a signaling bureau. If you are running it down to 15 November 2026, 31 January 2027 or a date of your own, we will price the NOC for one wire center cluster or one exchange group, per device, with the MTTR in writing. A one-page scope takes us a day.

Sources: FCC order 26-19 (26 March 2026); Broadband Breakfast on AT&T copper discontinuance (13 January 2026); Alianza on the Metaswitch acquisition (4 March 2025). Vendor figures are from each company’s own published material, as dated in the text.