Optimum (CSC, Suddenlink) phone number blocks and OCNs in the US

Optimum holds 4.3 million phone numbers in the United States, 0.2% of the numbers NANPA’s table of 2026-09-27 lists as allocated there, under 6 operating company numbers (OCNs); the largest, CSC VOICE, LLC (OCN 612K), holds 3.4 million. The carrier a phone lookup names for a number is the holder of the block the number sits in, as the regulator lists it: the original allocation, not the caller, the app or the network that serves a ported number today.

Brand	Optimum
Numbers held	4,285,000 (0.2% of the allocated numbers in NANPA’s table)
Operating company numbers	6
Codes held	631
Thousands-blocks held	4,131
Table	NANPA numbering reports, file dated 2026-09-27
Terms	no terms of use published (NANPA)
Grouped by	Spaw’s carrier brand map of 2026-09-24
Region	United States

The legal entities NANPA lists

Every holder in NANPA’s table that the brand map groups under Optimum, by the numbers allocated to it and with its operating company number (OCN), the code the table identifies a carrier by. Names are printed as the regulator writes them. Holdings are counted in numbers, not table rows, because rows differ in size: a central office code (NPA-NXX) is 10,000 numbers and a thousands-block 1,000. A pooled code counts for its code holder only where no thousands-block row of the table covers it, so no number is counted twice.

holder	ocn	codes	thousands-blocks	numbers	read as
CSC VOICE, LLC	612K	414	3,272	3,414,000	unsettled
CSC WIRELESS, LLC	425J	204	670	679,000	mobile
TCA COMMUNICATIONS, LLC DBA SUDDENLINK COMM - AR	048G	6	134	134,000	unsettled
CEBRIDGE TELECOM LA, LLC D/B/A SUDDENLINK COMM LA	260H	3	41	41,000	unsettled
CEBRIDGE TELECOM NM, LLC DBA SUDDENLINK COMM NM	243H	4	9	12,000	unsettled
CEBRIDGE TELECOM VA, LLC DBA SUDDENLINK COMM	229H	0	5	5,000	unsettled

How a lookup reads these numbers

The North American plan leaves a number’s line type to the holder of its block, so a lookup reads it from the holder: 0.0% of Optimum’s numbers read as VoIP, 15.8% as mobile, and for 84.2% the holder settles neither, so the line type stays fixed_line_or_mobile.

The reading is Spaw’s classification of each holder: the holder’s regulatory filing (in the US its FCC Form 499 filing type) and its own description, matched on the name the regulator’s table gives it. It is a lower bound, not a measurement of the numbers, and it says what a lookup answers, not what Optimum is.

The area codes with most of its numbers

Optimum’s entities hold numbers under 202 area codes. The share is its part of the numbers NANPA lists as allocated under each code.

code	place	numbers	share of the code
347	New York City, NY	361,000	4.6%
631	New York	329,000	4.2%
516	Nassau County, NY	212,000	2.7%
870	Arkansas	206,000	2.9%
973	New Jersey	200,000	2.6%
732	New Jersey	186,000	2.4%
914	Westchester County, NY	170,000	2.5%
845	New York	168,000	2.3%
201	New Jersey	150,000	1.9%
304	West Virginia	148,000	1.9%
203	Connecticut	131,000	1.7%
903	Texas	106,000	1.4%

Thousands-blocks in pooled codes

In a pooled US code NANPA assigns the code’s ten thousands-blocks one by one, often to carriers other than the code holder, and a lookup names the holder of the number’s own thousands-block where NANPA lists one. Optimum’s entities hold 4,131 thousands-blocks: 1,317 inside codes its own entities hold, 2,223 inside codes of other brands and 591 inside codes of holders the brand map does not group, which this page counts but does not name.

code holder’s brand	Optimum’s blocks inside
Verizon	568
AT&T	476
Lumen	334
T-Mobile	270
Inteliquent	155
Windstream	125

Other holders hold 4,301 thousands-blocks inside Optimum’s codes, 446 of them holders the brand map does not group. The largest: Inteliquent 1,296, T-Mobile 631, AT&T 465, Verizon 445, Bandwidth 380, Lumen 235.

Assignments by year

The codes and thousands-blocks the table still lists under Optimum’s entities, by the year NANPA dates their assignment. A block returned since is no longer in the table, so earlier years read low; 90.0% of the rows carry a date. NANPA dates nothing before 2001 and no retained block.

year	codes	thousands-blocks	numbers
2026	1	94	94,000
2025	8	59	62,000
2024	21	152	160,000
2023	4	30	37,000
2022	11	58	65,000
2021	13	57	59,000
2020	112	134	141,000
2019	86	325	325,000
2018	1	31	31,000
2017	0	5	5,000
2001–2016	263	2,820	2.9 million

What this page cannot say

A regulator’s table records the original allocation of each block, never who serves a number today: a number ported away from Optimum keeps its block, and a lookup still names the block’s holder for it.
The carrier a lookup names is not the caller, the app or the subscriber. Caller ID can be spoofed, so the holder of a calling number’s block may not have carried the call at all.
Spaw does no reverse lookup and names no subscriber: nothing here says who owns or uses any number.
Shares are shares of the regulator’s own table, not of subscribers, lines in service or traffic.
In a pooled US code a lookup names the holder of the number’s own thousands-block where NANPA lists one, otherwise the code holder; Canada’s table is code-level.
The grouping under Optimum is Spaw’s carrier brand map of 2026-09-24: legal entities, subsidiaries and former names under the brand the network trades as today. Networks change hands, and the map is reviewed at least yearly.

Optimum and the other brand names on this page are trademarks of their owners, used only to name the networks the regulators’ tables list. Spaw is not affiliated with any of them.

Other carriers in the United States

NANPA numbering reports file dated 2026-09-27 · carrier brand map 2026-09-24 · page changed 2026-09-27

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