NumberResearchThousands-blocks in 313-543
This prefix’s ten 1,000-number blocks and who holds each — 10 on record · from the daily NANPA thousands-block report, 09/20/2026
The ten 1,000-number thousand-blocks inside prefix 313-543 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 313 blocks
Most active assignees, all time — NPA 313
New assignments by month
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| — | 313-543-0XXX | 0000–0999 | Reserved | MICHIGAN BELL TEL CO | 9323 | DETROITZN5 | MI |
| — | 313-543-1XXX | 1000–1999 | Reserved | MICHIGAN BELL TEL CO | 9323 | DETROITZN5 | MI |
| — | 313-543-2XXX | 2000–2999 | Reserved | MICHIGAN BELL TEL CO | 9323 | DETROITZN5 | MI |
| 2013-09-09 | 313-543-3XXX | 3000–3999 | Assigned | WOW! INTERNET, CABLE AND PHONE | 961J | DETROITZN5 | MI |
| 2010-04-08 | 313-543-4XXX | 4000–4999 | Assigned | OMNIPOINT COMMUNICATIONS MIDWEST OPERATIONS, LLC | 2964 | DETROITZN5 | MI |
| 2006-04-25 | 313-543-5XXX | 5000–5999 | Assigned | PAETEC ITEL, LLC | 829J | DETROITZN5 | MI |
| — | 313-543-6XXX | 6000–6999 | Reserved | MICHIGAN BELL TEL CO | 9323 | DETROITZN5 | MI |
| — | 313-543-7XXX | 7000–7999 | Reserved | MICHIGAN BELL TEL CO | 9323 | DETROITZN5 | MI |
| 2008-02-12 | 313-543-8XXX | 8000–8999 | Assigned | 123.NET, LLC | 2550 | DETROITZN5 | MI |
| — | 313-543-9XXX | 9000–9999 | Reserved | MICHIGAN BELL TEL CO | 9323 | DETROITZN5 | MI |
Source: NANPA Thousands Block Assignment Report (All Regions, Public), file date 09/20/2026 — Tier A primary source, refreshed on every import. Viewing is free; bulk downloads require a membership.