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

STAMFORD prefixes in area code 325

NANPA records 4 assigned NXX blocks to rate center STAMFORD in area code 325, 1.0% of the 408 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. 4 holders hold those blocks, the largest being TEXAS COMMUNICATIONS, INC. (1), ONVOY SPECTRUM, LLC (1), ONVOY, LLC - TX (1). The earliest assignment on record here is 2018-05-30 and the most recent 2021-11-11. 3 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 203, 308, 475, 607 – overlay codes cover the same geography, so a rate center is served by all of them.

4 assigned blocks – 1% of 325
4 holders of record
3 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
325-250 TEXAS COMMUNICATIONS, INC. – no yes
325-299 Charter ONVOY SPECTRUM, LLC 2021-11-11 yes yes
325-399 Onvoy ONVOY, LLC - TX 2018-05-30 yes yes
325-773 AT&T SOUTHWESTERN BELL – 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
TEXAS COMMUNICATIONS, INC. – 1 25%
ONVOY SPECTRUM, LLC Charter 1 25%
ONVOY, LLC - TX Onvoy 1 25%
SOUTHWESTERN BELL AT&T 1 25%

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 STAMFORD in area code 325?

4 blocks: 250, 299, 399, 773. The table above gives the holder of each.

Which carriers have numbers in STAMFORD?

TEXAS COMMUNICATIONS, INC. (1 block), ONVOY SPECTRUM, LLC (1 block), ONVOY, LLC - TX (1 block), SOUTHWESTERN BELL (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is STAMFORD 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 325

All 408 prefixes in 325