NumberingData
Verified Nov 1, 2026 · Source: NANPA CO Code Assignment Records

CHARLESTN prefixes in area code 857

NANPA records 10 assigned NXX blocks to rate center CHARLESTN in area code 857, 2.8% of the 361 blocks assigned in the code. A rate center is the billing geography a block is allocated to – NANPA truncates the name to ten characters, so read it as a NANPA label rather than a town. 5 holders hold those blocks, the largest being OMNIPOINT MIAMI E LICENSE, LLC (4), ONVOY, LLC - MA (3), BANDWIDTH.COM CLEC, LLC - MA (1). The earliest assignment on record here is 2001-03-27 and the most recent 2023-08-17. 10 of them are in thousands-block pooling, so those prefixes are shared between carriers in 1,000-number lots. The same rate center name also appears in area codes 603, 617, 812, 930 – overlay codes cover the same geography, so a rate center is served by all of them.

10 assigned blocks – 2.8% of 857
5 holders of record
10 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
857-389 T-Mobile OMNIPOINT MIAMI E LICENSE, LLC 2001-12-14 yes yes
857-391 T-Mobile OMNIPOINT MIAMI E LICENSE, LLC 2021-12-03 yes yes
857-410 Bandwidth BANDWIDTH.COM CLEC, LLC - MA 2016-08-12 yes yes
857-452 T-Mobile OMNIPOINT MIAMI E LICENSE, LLC – yes yes
857-468 TON80 COMMUNICATIONS, LLC 2022-02-11 yes yes
857-497 T-Mobile OMNIPOINT MIAMI E LICENSE, LLC 2023-08-17 yes yes
857-577 Onvoy ONVOY, LLC - MA 2016-02-11 yes yes
857-588 Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC 2001-03-27 yes yes
857-837 Onvoy ONVOY, LLC - MA 2020-05-28 yes yes
857-971 Onvoy ONVOY, LLC - MA 2016-05-09 yes yes

The holder is who received the block from the numbering administrator. It is not necessarily the carrier serving a given number: numbers move with their owners, and a pooled block is shared.

Who holds the blocks

HolderBrandBlocksShare here
OMNIPOINT MIAMI E LICENSE, LLC T-Mobile 4 40%
ONVOY, LLC - MA Onvoy 3 30%
BANDWIDTH.COM CLEC, LLC - MA Bandwidth 1 10%
TON80 COMMUNICATIONS, LLC – 1 10%
MCIMETRO ACCESS TRANSMISSION SERVICES LLC Verizon 1 10%

Same rate center in other codes

Overlay codes cover the same geography, so one rate center is served by all of them.

Frequently asked

Which prefixes belong to CHARLESTN in area code 857?

10 blocks: 389, 391, 410, 452, 468, 497, 577, 588, 837, 971. The table above gives the holder of each.

Which carriers have numbers in CHARLESTN?

OMNIPOINT MIAMI E LICENSE, LLC (4 blocks), ONVOY, LLC - MA (3 blocks), BANDWIDTH.COM CLEC, LLC - MA (1 block), TON80 COMMUNICATIONS, LLC (1 block), MCIMETRO ACCESS TRANSMISSION SERVICES LLC (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is CHARLESTN a city?

It is a rate center – the unit NANPA allocates number blocks to. Its name is abbreviated to ten characters and is not necessarily a settlement: we print it as recorded rather than guess at the full name.

Other rate centers in 857

All 361 prefixes in 857