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

PORTAGSIUX prefixes in area code 636

NANPA records 7 assigned NXX blocks to rate center PORTAGSIUX in area code 636, 1.6% of the 435 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 SOUTHWESTERN BELL (3), ONVOY, LLC - MO (1), PAETEC ITEL, LLC (1). The earliest assignment on record here is 2001-05-10 and the most recent 2001-07-05. 7 of them are in thousands-block pooling, so those prefixes are shared between carriers in 1,000-number lots.

7 assigned blocks – 1.6% of 636
5 holders of record
7 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
636-400 Onvoy ONVOY, LLC - MO – yes yes
636-425 Windstream PAETEC ITEL, LLC – yes yes
636-426 T-Mobile T-MOBILE USA, INC. 2001-05-10 yes yes
636-434 AT&T SOUTHWESTERN BELL 2001-07-05 yes yes
636-648 TERRA NOVA TELECOM INC. – yes yes
636-753 AT&T SOUTHWESTERN BELL – yes yes
636-899 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
SOUTHWESTERN BELL AT&T 3 42.9%
ONVOY, LLC - MO Onvoy 1 14.3%
PAETEC ITEL, LLC Windstream 1 14.3%
T-MOBILE USA, INC. T-Mobile 1 14.3%
TERRA NOVA TELECOM INC. – 1 14.3%

Frequently asked

Which prefixes belong to PORTAGSIUX in area code 636?

7 blocks: 400, 425, 426, 434, 648, 753, 899. The table above gives the holder of each.

Which carriers have numbers in PORTAGSIUX?

SOUTHWESTERN BELL (3 blocks), ONVOY, LLC - MO (1 block), PAETEC ITEL, LLC (1 block), T-MOBILE USA, INC. (1 block), TERRA NOVA TELECOM INC. (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is PORTAGSIUX 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 636

All 435 prefixes in 636