NumberResearchThousands-blocks in 603-310
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 603-310 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
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| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2004-08-27 | 603-310-0XXX | 0000–0999 | Assigned | OTEL TELEKOM, INC. - NH | 9827 | BEDFORD | NH |
| 2022-09-29 | 603-310-1XXX | 1000–1999 | Assigned | TELNYX LLC | 073H | BEDFORD | NH |
| 2002-10-23 | 603-310-2XXX | 2000–2999 | Assigned | TELEPORT COMMUNICATIONS AMERICA, LLC - NH | 8299 | BEDFORD | NH |
| 2007-04-06 | 603-310-3XXX | 3000–3999 | Assigned | PAETEC ITEL, LLC | 829J | BEDFORD | NH |
| 2002-08-28 | 603-310-4XXX | 4000–4999 | Assigned | PAETEC ITEL, LLC | 829J | BEDFORD | NH |
| 2015-02-19 | 603-310-5XXX | 5000–5999 | Assigned | PAETEC ITEL, LLC | 829J | BEDFORD | NH |
| 2020-03-12 | 603-310-6XXX | 6000–6999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC - NH | 7778 | BEDFORD | NH |
| 2014-12-29 | 603-310-7XXX | 7000–7999 | Assigned | COMCAST IP PHONE, LLC | 318J | BEDFORD | NH |
| 2022-10-07 | 603-310-8XXX | 8000–8999 | Assigned | COMMIO, LLC | 939H | BEDFORD | NH |
| 2000-11-09 | 603-310-9XXX | 9000–9999 | Assigned | PAETEC ITEL, LLC | 829J | BEDFORD | NH |
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.