NumberResearchThousands-blocks in 508-256
This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/19/2026
The ten 1,000-number thousand-blocks inside prefix 508-256 and who was initially assigned each. Under pooling these blocks often belong to different carriers — the single prefix-level “assignee” is usually just the pool / code holder, not who holds the numbers. ← all 508 blocks
Most active assignees, all time — NPA 508
New assignments by month
Sep 2026
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| — | 508-256-0XXX | 0000–0999 | Reserved | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | BROCKTON | MA |
| 2026-03-04 | 508-256-1XXX | 1000–1999 | Assigned | TERRA NOVA TELECOM INC. | 145J | BROCKTON | MA |
| 2025-07-02 | 508-256-2XXX | 2000–2999 | Assigned | TERRA NOVA TELECOM INC. | 145J | BROCKTON | MA |
| 2019-02-28 | 508-256-3XXX | 3000–3999 | Assigned | COMCAST IP PHONE, LLC | 318J | BROCKTON | MA |
| — | 508-256-4XXX | 4000–4999 | Available | BROCKTON | MA | ||
| — | 508-256-5XXX | 5000–5999 | Reserved | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | BROCKTON | MA |
| — | 508-256-6XXX | 6000–6999 | Reserved | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | BROCKTON | MA |
| — | 508-256-7XXX | 7000–7999 | Reserved | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | BROCKTON | MA |
| — | 508-256-8XXX | 8000–8999 | Reserved | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | BROCKTON | MA |
| 2019-01-24 | 508-256-9XXX | 9000–9999 | Assigned | ONVOY, LLC - MA | 892D | BROCKTON | MA |
Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/19/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.