NumberResearchThousands-blocks in 603-200
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 603-200 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 603 blocks
Most active assignees, all time — NPA 603
New assignments by month
Sep 2026
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Dec 2025
Nov 2025
Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2011-08-16 | 603-200-0XXX | 0000–0999 | Assigned | COMCAST IP PHONE, LLC | 318J | NEWMARKET | NH |
| 2023-07-07 | 603-200-1XXX | 1000–1999 | Assigned | TELNYX LLC | 073H | NEWMARKET | NH |
| 2015-10-05 | 603-200-2XXX | 2000–2999 | Assigned | COMCAST IP PHONE, LLC | 318J | NEWMARKET | NH |
| 2013-02-28 | 603-200-3XXX | 3000–3999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - NH | 7778 | NEWMARKET | NH |
| 2016-01-06 | 603-200-4XXX | 4000–4999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - NH | 7778 | NEWMARKET | NH |
| 2023-02-27 | 603-200-5XXX | 5000–5999 | Assigned | TELEPORT COMMUNICATIONS AMERICA, LLC - NH | 8299 | NEWMARKET | NH |
| 2012-12-14 | 603-200-6XXX | 6000–6999 | Assigned | TELEPORT COMMUNICATIONS AMERICA, LLC - NH | 8299 | NEWMARKET | NH |
| 2023-03-31 | 603-200-7XXX | 7000–7999 | Assigned | TELNYX LLC | 073H | NEWMARKET | NH |
| 2024-03-13 | 603-200-8XXX | 8000–8999 | Assigned | TELNYX LLC | 073H | NEWMARKET | NH |
| 2023-01-10 | 603-200-9XXX | 9000–9999 | Assigned | TELNYX LLC | 073H | NEWMARKET | NH |
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.