Keep your existing phone system, modernise what's behind it. SIP trunks replace legacy ISDN lines with resilient voice-over-IP connectivity — cutting costs and future-proofing ahead of the ISDN switch-off.
Support from Dublin, Cork, Galway and Belfast — never outsourced.
And 98% client retention that speaks for itself.
Independently audited service delivery, every year since 2021.
Real-time dashboards and measurable commitments.
A virtual phone line delivered over your internet connection, connecting your on-premise PBX to the telephone network — replacing physical ISDN circuits.
ISDN networks are being switched off — migration is inevitable, and moving early captures the cost savings and avoids a forced rush.
It depends on your existing PBX investment, contact patterns and Microsoft usage — we'll assess and recommend the best-fit path, not just the newest one.
Business broadband and dedicated leased lines from Nostra — resilient, fast connectivity with proactive monitoring for Irish businesses.
Learn more →SD-WAN and managed business WiFi from Nostra — intelligent multi-site networking and wall-to-wall wireless coverage, fully managed.
Learn more →Cloud phone systems and hosted PBX from Nostra — modern VoIP telephony with call routing, mobile apps and CRM integration for Irish businesses.
Learn more →Written by the Nostra team | Reviewed October 2026
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