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Area Codes 301 & 240
Telephone Central Office Building Pictures

The following are respresntative examples of telephone central office buildings in Area Codes 301 & 240 (western/southern MD).

Click on the pictures below for a larger version.


Ashton

"Olney Oakdale"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
OLNYMDOKDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 260, 570, 774, 924

Notes:
Also servers parts of Washington Zone 12. Source: GSV

 

Bittinger

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
BTNRMDBRRS1

Switch Type:
Genband/Nortel RSC

Prefixes Served:
(301) 245

Notes:
Source: GSV

 

Brandywine

Photo 2 (old CO)

Listing Updated:
December 2010

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
BRNDMDBERS0

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 371, 782

Notes:
Main photo is of new building, which is just to the right of the original building (photo 2).
Also serves Washington Zone 16 (301-371)

 

Brandywine

"Baden"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
BADNMDBNRS0

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 579, 888

Notes:
Also serves parts of Washington Zone 16. Source: GSV

 

Buckeystown

Listing Updated:
December 2005

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
BCTWMDBTRS1

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(240) 699
(301) 874

Notes:
Source: Telebeans

 

Clear Spring

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
CLSPMDCSRS0

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 842

Notes:
Source: GSV

 

Cumberland

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
CMLDMDCMDS0

Switch Type:
Genband/Nortel DMS-100/200

Prefixes Served:
(301) 722-4, 759, 777, 784
(814) 767

Notes:
Serves State Line, PA (814-767) through an agreement with CenturyLink. Used to serve a ratecenter in WV prior to the spin off of Verizon i WV to Frontier in 2010. Source: GSV

 

Cumberland

"Cresaptown"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
CSTWMDCRDS0

Switch Type:
Genband/Nortel DMS-100

Prefixes Served:
(240) 362
(301) 729

Notes:
Source: GSV

 

Emmitsburg

Listing Updated:
December 2005

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
EMBGMDEMRS0

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 447

Notes:
Source: Telebeans

 

Frederick

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
FRDRMDFRDS0

Switch Type:
Alcatel/Lucent 5ESS Host

Prefixes Served:
(301) 418

Notes:
Serves a number of remotes. Source: GSV

 

Friendsville

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
FIVLMDFRRS0

Switch Type:
Genband/Nortel RSC

Prefixes Served:
(301) 746

Notes:
Source: GSV

 

Frostburg

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
FSBGMDFSDS0

Switch Type:
Genband/Nortel DMS-100

Prefixes Served:
(301) 687, 689

Notes:
Source: GSV

 

Gaithersburg

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
GTBGMDGBDS0
GTBGMDGBPS0

Switch Type:
DS0: Alcatel/Lucent 5ESS
PS0: Avaya/Nortel Succesion CS-1000

Prefixes Served:
DS0: (240) 276, 386, 631-2, 683 (301) 212, 216, 240, 258, 330, 417, 519, 527, 548. 590, 640, 670, 721, 840, 869, 921, 926, 947-8, 956, 963, 975, 977-9,987, 990

PS0: (301) 355, 740

Notes:
Also serves parts of the "Washington Zone 10" ratecenter. This CO building contains both a 5ESS and a packet switch (installed 2004).  Source: GSV

 

Hagerstown

Listing Updated:
December 2005

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
HGTWMDHGDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(240) 313, 420, 527
(301) 393, 665, 714, 733, 739, 745, 766, 790-1, 797

Notes:
Source: Telebeans

 

Highfield

Listing Updated:
December 3005

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
HGFLMDHFRS0

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 241

Notes:
Source: Telebeans

 

Indian Head

Listing Updated:
January 2004

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
INHDMDINRS0

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 743-4

Notes:
Source: Telebeans

 

Laurel

"Muirkirk"

Listing Updated:
December 2005

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
MRKKMDMKDS0

Switch Type:
Genband/Nortel DMS-100

Prefixes Served:
(240) 264
(301) 210, 419, 425-6, 566, 716
(410) 606, 705, 722, 738, 791, 813, 815, 898

Notes:
Serves parts of Laurel, Washington Zone 13, and Waterloo rate centers. Source: Telebeans

 

La Plata

Listing Updated:
August 2009

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
LPLTMDLADS0

Switch Type:
Alcatel/Lucent 5ESS Host

Prefixes Served:
(301) 392, 609, 753, 922, 934

Notes:
Also serves part of Waldorf and Oxon Hill (Washington Zone 6).

 

Leonardtown

Listing Updated:
March 2010

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
LNTWMDLTRS0

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 475, 997

Notes:
 

 

Leonardtown

"Hollywood"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
HLWDMDHWRS0

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 373

Notes:
Source: GSV

 

Leonardtown

"Milestown"

Photo 2 | Photo 3

Listing Updated:
March 2010

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
MLTWMDMLRS0

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 769

Notes:
Note that the pay phone has been removed and the cornerstone when the building was built (most likely when this area went dial)

 

Lexington Park/Great Mills

"Lexington Park"

Listing Updated:
March 2010

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
LXPKMDLXDS0

Switch Type:
Alcatel/Lucent 5ESS Host

Prefixes Served:
(240) 725, 895
(301)  737, 826, 862-3, 866

Notes:
CO is in a rough neighborhood. Notice that is is behind  a fence.  It is next to a good sized city park.

 

Lexington Park/Great Mills

"Valley Lee"

Photo 2 | Photo 3

Listing Updated:
March 2010

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
VYLEMDVLRS0

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 994

Notes:
Located out in the middle of nowhere, next to a volunteer fire station. Note in Picture 3 the date the building was built (most likely when this area went dial).

 

Lonaconing

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
LNCNMDLNRS0

Switch Type:
Genband/Nortel RSC

Prefixes Served:
(301) 463

Notes:
Source: GSV

 

Mechanicsville

Listing Updated:
April 2010

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
MCHVMDMCRS1

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 290, 472, 884

Notes:
 

 

Middletown

"Braddock Heights"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
BRHGMDBHRS1

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 371, 473

Notes:
Also serves parts of Frederick, Source: GSV

 

Mount Airy

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
MTARMDMARS1

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 829

Notes:
Source: GSV

 

Oakland

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
OKLDMDOKDS0

Switch Type:
Genband/Nortel DMS-100

Prefixes Served:
(301) 334, 553

Notes:
Source: GSV

 

Poolsville

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
PLVLMDPVRS0

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 349, 407, 605

Notes:
Serves parts of Gaithersburg. Source: GSV

 

Ridge

Listing Updated:
March 2010

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
RIDGMDRIRS0

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 872

Notes:
 

 

Thurmont

Listing Updated:
December 2005

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
THRMMDTHRS0

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 271

Notes:
Source: Telebeans

 

Tompkinsville

Listing Updated:
March 2010

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
TMVLMDTKRS0

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 259

Notes:
 

 

Waldorf

Listing Updated:
March 2004

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
WDRFMDWDDS0

Switch Type:
Alcatel/Lucent 5ESS Host

Prefixes Served:
(301) 374, 396, 632, 638, 645, 705, 764, 818, 843, 870, 885, 893

Notes:
Also serves parts of Washington Zone 6 rate center. Source: Telebeans

 

Washington Zone 2

"Bethesda Bradley"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
BTHSMDBDDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 299, 365, 469, 765, 767, 983

Notes:
Serves parts of Washington Zone 10. Source: GSV

 

Washington Zone 2

"Bethesda Wildwood"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
BTHSMDWWDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(240) 694
(301) 214, 295, 319, 380, 493, 530, 564, 571, 581, 803, 896-7

Notes:
Source: GSV

 

Washington Zone 2

"Bethesda Wood Acres"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
BTHSMDWADS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 227, 229, 243, 263, 320

Notes:
Source: GSV

 

Washington Zone 2

"Chevy Chase Bethesda"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
CHCHMDBEDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(240) 497
(301) 215, 280, 347, 492, 652, 654, 656-7, 664, 718, 771, 907, 913, 941, 951, 961, 986
 

Notes:
Source: GSV

 

Washington Zone 3

"Hyattsville Riggs Road"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
HYVLMDRIDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 408, 422, 431, 434, 439, 445, 701, 923, 935

Notes:
Serves parts of Washington Zones 4 & 13. Source: GSV

 

Washington Zone 3

"Silver Spring"

Listing Updated:
January 2005

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
SLSPMDSSDS0

Switch Type:
Alcatel/Lucent 5ESS-2000

Prefixes Served:
(240) 662
(301) 285, 427, 495, 562-3, 565, 578, 585, 587-9, 608, 626, 650, 819, 930

Notes:
Source: Telebeans

 

Washington Zone 3

"Silver Spring Northwood"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
SLSPMDNWDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 592-3, 649, 681, 754, 905

Notes:
Serves parts of Washington Zone 11. Source: GSV

 

 

Washington Zone 4

"Hyattsville"

 

Listing Updated:
January 2006

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
HYVLMDHYDS0

Switch Type:
Genband/Nortel DMS-100

Prefixes Served:
(240) 582
(301) 209, 239, 277, 403, 436, 454, 532, 699, 779, 851-2, 864, 887, 927, 985

Notes:
Source: Telebeans

 

Washington Zone 4

"Landover"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
LDVRMDLODS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 226, 322, 341, 386, 583, 618, 636, 772-3, 883, 925

Notes:
Serves parts of Washington Zone 5. Source: GSV

 

Washington Zone 4

"Lanham"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
LNHMMDLNDS0

Switch Type:
Nokia Siemens EWSD

Prefixes Served:
(301) 306, 429, 459, 552, 577, 731, 794, 918

Notes:
Serves parts of Washington Zones 13 & 14. Source: GSV

 

Washington Zone 5

"Capitol Heights"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
CPHGMDCADS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 324, 333, 336, 350, 499, 808

Notes:
Source: GSV

 

Washington Zone 5

"Suitland"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
STLDMDSLDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 420, 516, 568, 669, 735-6, 763, 817, 967

Notes:
Source: GSV

 

Washington Zone 5

"Temple Hills"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
TMHLMDTHDS0

Switch Type:
Genband/Nortel DMS-100

Prefixes Served:
(240) 695
(301) 238, 316, 423, 505, 630, 702, 836, 894, 899

Notes:
Source: GSV

 

Washington Zone 6

"Allentown"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
ALTWMDATDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 234, 248, 265, 297, 433, 449

Notes:
Source: GSV

 

Washington Zone 6

"Ft. Washington - Chapel Hill"

Listing Updated:
January 2004

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
FTWSMDCPDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 203, 292

Notes:
Source: Telebeans

 

Washington Zone 6

"Oxon Hill"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
OXHLMDOHDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 521, 567, 686, 749,839

Notes:
Source: GSV

 

Washington Zone 11

"Rockville Montrose"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
RKVLMDMRDS0
RKVLMDMRRS1

Switch Type:
DS0: Alcatel/Lucent 5ESS
DS1: Alcatel/Lucent 5ESS Remote

Prefixes Served:
DS0: (240) 221
DS0: (301) 230-1, 25, 382, 413, 468, 522, 770, 816, 881, 984, 998
DS1: (301) 443

Notes:
Source: GSV

 

Washington Zone 11

"Silver Spring Norbeck"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
SLSPMDNBDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 438, 460, 598, 603, 871

Notes:
Serves parts of Washington Zone 12. Source: GSV

 

Washington Zone 11

"Wheaton"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
WHTNMDWTDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(240) 292
(301) 929, 933, 946, 949, 962

Notes:
Source: GSV

 

Washington Zone 12

"Silver Spring Colesville"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
SLSPMDCVDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 236, 384, 388, 421, 476, 622, 625, 680, 879, 940, 989

Notes:
Serves parts of Washington Zone 3 and Ashton. Source: GSV

 

Washington Zone 13

"Beltsville"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
BTVLMDBVDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 394, 572, 586, 595. 796, 847, 890, 902, 931, 937

Notes:
Serves part of Washington Zone 3. Source: GSV

 

Washington Zone 13

"College Park - Berwyn"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
CLPKMDBWDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(240) 624, 684
(301) 220, 286, 313, 344-5, 397, 441, 446, 474, 486, 488-9, 507, 513, 614-5, 901, 982, 993

Notes:
Source: GSV

 

Washington Zone 14

"Bowie"

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
BOWIMDBODS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 262, 352, 464, 805, 809, 860

Notes:
Source: GSV

 

Washington Zone 14

"Upper Marlboro Church Rd."

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
UPMRMDCCDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 218, 249, 390, 430

Notes:
Source: GSV

 

Washington Zone 15

"Marlboro"

Listing Updated:
December 2005

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
MRBOMDMBDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(301) 574, 627, 780, 952
(410) 741

Notes:
Also serves parts of West River rate center. Source: Telebeans

 

Washington Zone 16

"Clinton"

Listing Updated:
July 2014

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
CLTNMDCLDS0

Switch Type:
Alcatel/Lucent 5ESS

Prefixes Served:
(240) 318
(301) 599, 856, 868, 877

Notes:
Serves parts of Washington Zone 5. Source: GSV

 

Williamsport

Listing Updated:
May 2011

Operating Company:
Verizon/Bell Atlantic/C&P of Maryland

CLLI:
WLPTMDWPRS2

Switch Type:
Alcatel/Lucent 5ESS Remote

Prefixes Served:
(301) 223, 582

Notes:
Serves parts of Hagerstown. Source: GSV

 

 


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Page last modified July 23, 2014
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