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

FRNK GRNLF prefixes in area code 510

NANPA records 25 assigned NXX blocks to rate center FRNK GRNLF in area code 510, 3.2% of the 785 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. 12 holders hold those blocks, the largest being PACIFIC BELL (10), MCIMETRO ACCESS TRANSMISSION SERVICES LLC (2), LEVEL 3 COMMUNICATIONS, LLC - CA (2). The earliest assignment on record here is 2001-05-17 and the most recent 2019-04-17. 19 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 code 341 – overlay codes cover the same geography, so a rate center is served by all of them.

25 assigned blocks – 3.2% of 510
12 holders of record
19 of them pooled in 1,000-number lots

Prefixes assigned here

PrefixHolder of recordAssignedPooledIn service
510-240 Lumen LEVEL 3 TELECOM OF CALIFORNIA, LP - CA – yes yes
510-324 AT&T PACIFIC BELL – yes yes
510-400 Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC – yes yes
510-401 TPx U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS – yes yes
510-404 Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA – yes yes
510-429 AT&T PACIFIC BELL – no yes
510-431 Lumen LEVEL 3 COMMUNICATIONS, LLC - CA – yes yes
510-441 AT&T PACIFIC BELL – yes yes
510-462 Onvoy ONVOY, LLC - CA 2016-05-04 yes yes
510-471 AT&T PACIFIC BELL – no yes
510-474 Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC – yes yes
510-475 AT&T PACIFIC BELL – no yes
510-476 AT&T PACIFIC BELL – yes yes
510-477 AT&T PACIFIC BELL – no yes
510-487 AT&T PACIFIC BELL – no yes
510-489 AT&T PACIFIC BELL – no yes
510-491 AT&T TELEPORT COMMUNICATIONS AMERICA, LLC - CA – yes yes
510-675 AT&T PACIFIC BELL – yes yes
510-870 Lumen LEVEL 3 COMMUNICATIONS, LLC - CA – yes yes
510-941 Comcast COMCAST PHONE OF CALIFORNIA, LLC 2016-12-12 yes yes
510-945 AT&T NEW CINGULAR WIRELESS PCS, LLC 2015-04-10 yes yes
510-952 T-Mobile METROPCS, INC. 2001-05-17 yes yes
510-961 Bandwidth BANDWIDTH.COM CLEC, LLC - CA 2019-04-17 yes yes
510-972 Comcast COMCAST PHONE OF CALIFORNIA, LLC – yes yes
510-991 Onvoy ONVOY, LLC - CA – 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
PACIFIC BELL AT&T 10 40%
MCIMETRO ACCESS TRANSMISSION SERVICES LLC Verizon 2 8%
LEVEL 3 COMMUNICATIONS, LLC - CA Lumen 2 8%
ONVOY, LLC - CA Onvoy 2 8%
COMCAST PHONE OF CALIFORNIA, LLC Comcast 2 8%
LEVEL 3 TELECOM OF CALIFORNIA, LP - CA Lumen 1 4%
U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS TPx 1 4%
MCIMETRO ACCESS TRANSMISSION SERVICES LLC - CA Verizon 1 4%
TELEPORT COMMUNICATIONS AMERICA, LLC - CA AT&T 1 4%
NEW CINGULAR WIRELESS PCS, LLC AT&T 1 4%
METROPCS, INC. T-Mobile 1 4%
BANDWIDTH.COM CLEC, LLC - CA Bandwidth 1 4%

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 FRNK GRNLF in area code 510?

25 blocks: 240, 324, 400, 401, 404, 429, 431, 441, 462, 471, 474, 475 and 13 more, all listed in the table above.

Which carriers have numbers in FRNK GRNLF?

PACIFIC BELL (10 blocks), MCIMETRO ACCESS TRANSMISSION SERVICES LLC (2 blocks), LEVEL 3 COMMUNICATIONS, LLC - CA (2 blocks), ONVOY, LLC - CA (2 blocks), COMCAST PHONE OF CALIFORNIA, LLC (2 blocks), LEVEL 3 TELECOM OF CALIFORNIA, LP - CA (1 block). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.

Is FRNK GRNLF 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 510

All 785 prefixes in 510