NumberResearchThousands-blocks in 503-610
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 503-610 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 503 blocks
Most active assignees, all time — NPA 503
New assignments by month
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Oct 2025
| Assigned | Thousands-block | Last 4 digits | Status | Assignee | OCN | Rate center | State |
|---|---|---|---|---|---|---|---|
| 2013-04-03 | 503-610-0XXX | 0000–0999 | Assigned | BANDWIDTH.COM CLEC, LLC - OR | 076F | SHERWOOD | OR |
| 2006-08-10 | 503-610-1XXX | 1000–1999 | Assigned | COMCAST IP PHONE, LLC | 318J | SHERWOOD | OR |
| 2010-08-26 | 503-610-2XXX | 2000–2999 | Assigned | BANDWIDTH.COM CLEC, LLC - OR | 076F | SHERWOOD | OR |
| 2011-02-23 | 503-610-3XXX | 3000–3999 | Assigned | BANDWIDTH.COM CLEC, LLC - OR | 076F | SHERWOOD | OR |
| 2012-11-20 | 503-610-4XXX | 4000–4999 | Assigned | ONVOY, LLC - OR | 750E | SHERWOOD | OR |
| 2010-05-20 | 503-610-5XXX | 5000–5999 | Assigned | BANDWIDTH.COM CLEC, LLC - OR | 076F | SHERWOOD | OR |
| 2013-04-03 | 503-610-6XXX | 6000–6999 | Assigned | BANDWIDTH.COM CLEC, LLC - OR | 076F | SHERWOOD | OR |
| 2007-06-28 | 503-610-7XXX | 7000–7999 | Assigned | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | SHERWOOD | OR |
| 2008-10-30 | 503-610-8XXX | 8000–8999 | Assigned | BANDWIDTH.COM CLEC, LLC - OR | 076F | SHERWOOD | OR |
| — | 503-610-9XXX | 9000–9999 | Reserved | MCIMETRO ACCESS TRANSMISSION SERVICES LLC | 7229 | SHERWOOD | OR |
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.