AT&T 4ESS Tandem List

 

The following is a work in progress in trying to maintain an active catalog of the Number 4 Electronic Switching System (#4ESS) Class 4 Tandem list for the AT&T long distance network. This list is a successor to the original list made by the late telephone historian and researcher Mark Cuccia (1961-2014) to try to encompass the changes in the #4ESS network since his passing.

The #4ESS switch was first installed in Chicago, IL in 1976 as the successor to the 4A crossbar switch. Over 100 #4ESS switches were installed in the PSTN by the early 1990s for AT&T Long Lines, and a number of them were also used for the regional Bell operating companies. A second batch of #4ESS switches (what I call “2nd Generation”) were installed in 1998-1999 and were the last #4ESS switches installed in the PSTN, with the one in Atlanta (number 146-T) being the last one ever.

Starting in or around 2012, a new batch of #4ESS type Class 4 switches were starting to show up in the PTSN. This is the successor switch called the Next Generation 4ESS or N4E. The N4E emulates the #4ESS software in a new hardware environment. The main difference to the end user is that the tandem recordings are very clean (no magnetic drums) and sound a bit robotic in nature.

This list not only contains the #4ESSes in the network, but the new N4E switches as well. In some cases, there are N4E switches that are replacing 4ESS switches, and in some cases they are brand new to the network (those numbering 147 and higher). It is assumed that the new N4Es are replacing the #5ESS switches that were originally installed to be “edge tandems” in the AT&T network and upgrading them to full Class 4 tandems.

The locations for the new N4E switches are best guesses, and in some cases appears to be replacing existing #4ESS switches and taking on new identities, while in other cases they take on the old trailer code of the #4ESS that they replaced.

Trailer
Code
(xxx-T)	Location		Type	Install Date	Notes
001	WINDERMERE FL		4ESS	(03/1991)	Possibly retired?
002	ALBUQUERQUE 2 NM	4ESS	(11/1977)	Mexican gateway
003	ALBANY 3 NY		4ESS	(01/1982)	
004	ANAHEIM 3 CA		4ESS	(03/1981)	Possibly replaced with 158-T?
005	ARLINGTON 3 VA		4ESS	(04/1982)	
006	ATLANTA 5 GA		4ESS	(03/1982)	
007	ATLANTA 4 GA		N4E	Replaced	Caribbean gateway
008	AUSTIN 2 TX		4ESS	(01/1987)	
009	BUFFALO 2 NY		4ESS	(06/1984)	Canadian Gateway
010	BALTIMORE 10 MD		4ESS	(08/1980)	
011	BIRMINGHAM 2 AL		4ESS	(04/1981)	
012	BATON ROUGE 2 LA	4ESS	(03/1984)	
013	NEW YORK 5410 NY	4ESS	(07/1991)	
014	CHICAGO 9 IL		4ESS	(08/1987)	
015	CHARLOTTE 3 NC		4ESS	(05/1980)	
016	CHARLESTON 2 WV		4ESS	(02/1982)	
017	CLEVELAND 3 OH		4ESS	(12/1979)	
018	COLUMBIA 2 SC		4ESS	(11/1981)	
019	COLUMBUS 3 OH		4ESS	(04/1977)	
020	COLORADO SPRINGS 2 CO	4ESS	(10/1981)	
021	CAMBRIDGE 19 MA		4ESS	(12/1984)	
022	CAMDEN 3 NJ		4ESS	(04/1979)	
023	CINCINNATI 2 OH		4ESS	(06/1979)	
024	DES MOINES 2 IA		N4E	Replaced	
025	DALLAS 3 TX		4ESS	(12/1976)	
026	DALLAS 4 TX		4ESS	(04/1981)	Possibly replaced with 154-T?
027	DENVER 5 CO		4ESS	(11/1979)	
028	DETROIT 3 MI		4ESS	(04/1981)	(Disconnected circa 2003?)
029	DAYTON 2 OH		4ESS	(02/1987)	
030	FREEHOLD 2 NJ		4ESS	(05/1978)	
031	FRAMINGHAM 4 MA		4ESS	(05/1987)	
032	FORT WORTH 2 TX		N4E	Replaced	
033	GRAND RAPIDS 3 MI	4ESS	(05/1984)	
034	GREENSBORO 3 NC		4ESS	(03/1981)	
035	GARDENA 3 CA		4ESS	(06/1987)	
036	HARRISBURG 2 PA		N/A	Replaced	Changed to a 5ESS
037	HOUSTON 4 TX		N4E	Replaced	
038	HOUSTON 5 TX		4ESS	(07/1988)	
039	INDIANAPOLIS 2 IN	4ESS	(10/1980)	
040	JACKSON 2 MS		4ESS	(04/1983)	
041	JACKSONVILLE 3 FL	4ESS	(12/1976)	Caribbean gateway
042	KNOXVILLE 2 TN		4ESS	(12/1980)	
043	KANSAS CITY 2 MO	N4E	Replaced	
044	LANSING 3 MI		4ESS	(05/1987)	
045	LOS ANGELES 5 CA	4ESS	(02/1983)	
046	LOS ANGELES 6 CA	4ESS	(04/1988)	
047	LOUISVILLE 2 KY		4ESS	(07/1980)	
048	LITTLE ROCK 2 AR	N4E	Replaced	
049	MACON 3 GA		4ESS	(04/1987)	
050	MIDLAND 2 TX		4ESS	(10/1983)	
051	MEMPHIS 2 TN		4ESS	(02/1981)	
052	MANCHESTER 3 NH		4ESS	(04/1982)	
053	(presently unassigned)	N/A	N/A	N/A
054	MINNEAPOLIS 3 MN	4ESS	(05/1980)	Canadian Gateway
055	MINNEAPOLIS 4 MN	4ESS	(06/1988)	
056	MONTGOMERY 2 AL		N4E	Replaced
057	NORFOLK 4 VA		4ESS	(04/1981)	
058	NASHVILLE 2 TN		N4E	Replaced	
059	NEW HAVEN 5 CT		4ESS	(10/1981)	
060	NEW ORLEANS 3 LA	4ESS	(06/1980)	
061	NEWARK 8 NJ		4ESS	(06/1980)	
062	NEW YORK 24 NY		4ESS	(04/1978)	
063	NEW YORK 51 NY		4ESS	(11/1984)	
064	NEW YORK 5450 NY	4ESS	(01/1981)	
065	NEW YORK 12 NY(QUEENS)	N4E	Replaced	"(Regal Park, QUEENS)"
066	OJUS 3 FL		4ESS	(05/1978)	
067	OAKBROOK 2 IL		4ESS	(03/1981)	
068	OAKBROOK 3 IL		4ESS	(06/1988)	
069	OKLAHOMA CITY 2 OK	4ESS	(05/1979)	
070	OAKLAND 6 CA		4ESS	(08/1981)	
071	OMAHA 2 NE		N4E	Replaced	
072	ORLANDO 3 FL		4ESS	(09/1980)	
073	PEORIA 3 IL		4ESS	(02/1983)	
074	PHILADELPHIA 4 PA	4ESS	(05/1980)	
075	PHOENIX 3 AZ		4ESS	(09/1980)	
076	PITTSBURGH 3 PA		4ESS	(11/1977)	
077	PORTLAND 3 OR		4ESS	(04/1979)	Alaska Gateway
078	RICHMOND 2 VA		4ESS	(05/1979)	
079	ROCKY MOUNT 3 NC	4ESS	(06/1982)	(was United-Carolina)
080	ROCHELLE PARK 3 NJ	4ESS	(08/1982)	
081	RENO 4 NV		4ESS	(05/1982)	
082	SOUTH BEND 3 IN		4ESS	(04/1987)	
083	SACRAMENTO 4 CA		N4E	Replaced	Hawaii gateway
084	SHERMAN OAKS 5 CA	4ESS	(06/1985)	Pacific gateway
085	STOCKTON 3 CA		4ESS	(03/1984)	
086	SALT LAKE CITY 2 UT	4ESS	(04/1982)	Canadian Gateway
087	SAN ANTONIO 2 TX	4ESS	(05/1977)	Mexican gateway
088	SAN DIEGO 3 CA		N4E	Replaced	Only heard locally
089	SAN FRANCISCO 4 CA	4ESS	(06/1985)	
090	SAN JOSE 3 CA		4ESS	(03/1982)	
091	SPRINGFIELD 2 IL	4ESS	(04/1985)	
092	SPRINGFIELD 3 MA	4ESS	(05/1980)	Canadian Gateway
093	SPOKANE 2 WA		4ESS	(10/1982)	Canadian Gateway
094	SAINT LOUIS 3 MO	N4E	Replaced	
095	SEATTLE 4 WA		4ESS	(05/1980)	Canadian/Alaska Gateway
096	SYRACUSE 2 NY		4ESS	(03/1985)	
097	TAMPA FL		4ESS	(11/1986)	
098	TOLEDO 2 OH		4ESS	(04/1984)	
099	TULSA 2 OK		4ESS	(06/1980)	
100	WASHINGTON 6 DC		4ESS	(03/1978)	
101	WAYNE 2 PA		4ESS	(09/1977)	Possibly replaced?
102	WICHITA 2 KS		4ESS	(04/1981)	
103	WHITE PLAINS 3 NY	4ESS	(01/1987)	Atlantic gateway
104	WHITE PLAINS 5 NY	4ESS	(08/1980)	Canadian Gateway
105	WAUKESHA 3 WI		4ESS	(03/1979)	
106	WEST PALM BEACH 4 FL	4ESS	(08/1981)	Caribbean gateway
107	AKRON 4 OH		4ESS	(04/1989)	
108	ATLANTA 7 GA		4ESS	(11/1988)	
109	BLOOMINGTON 2 IN	4ESS	(11/1989)	
110	CHICAGO 11 IL		4ESS	(01/1990)	
111	NEW YORK 55 NY		4ESS	(11/1988)	Atlantic gateway
112	PLYMOUTH 2 MI		4ESS	(12/1989)	
113	SAN BERNARDINO 2 CA	4ESS	(03/1989)	
114	TUCSON 3 AZ		4ESS	(10/1989)	
115	PITTSBURGH 9 PA		4ESS	(12/1988)	Atlantic gateway
116	OMAHA 3 NE		4ESS	(07/1990)	
117	HAMILTON SQUARE 2 NJ	4ESS	(07/1991)	
118	WORCESTER 3 MA		4ESS	(12/1991)	
119	CHESHIRE CT		4ESS	(01/1992)	
120	NEW YORK 25 NY		4ESS	(02/1992)	
121	HILLSBORO MO		4ESS	(05/1992)	
122	FINKSBURG MD		4ESS	(07/1992)	
123	ADAMS TX		4ESS	(10/1992)	
124	PLANO IL		4ESS	(12/1992)	(standby tandem)
125	ELLISVILLE FL		4ESS	(10/1992)	
126	MONTICELLO 2 GA		4ESS	(10/1992)	
127	CEDAR KNOLLS 2 NJ	4ESS	(10/1992)	
128	TACOMA 2 WA		4ESS	(12/1992)	
129	DUNNIGAN CA		4ESS	(06/1993)	
130	GARDENA 4 CA		4ESS	(04/1993)	Possibly replaced with 152-T?
131	FORT LAUDERDALE FL	4ESS	(05/1993)	
132	MADISON 3 WI		4ESS	(11/1992)	
133	WHITE PLAINS 4 NY	4ESS	(08/1993)	
134	MARKHAM ON    (905-U2)	4ESS	(06/1993)	UNITEL (Canada)
135	CHERRYVILLE NJ		4ESS	(05/1993)	
136	CAMBRIDGE MA		4ESS	(06/1993)	
137	ALDERGROVE BC (604-U2)	4ESS	(08/1993)	UNITEL (Canada)
138	OXNARD CA		4ESS	(07/1993)	
139	ANCHORAGE AK		4ESS	(03/1996)	ALASCOM
140	MESA AZ		4ESS 2nd Gen	(1998/1999)	
141	DURHAM NC	4ESS 2nd Gen	(1998/1999)	
142	DENVER 6 CO	4ESS 2nd Gen	(1998/1999)	
143	FORT MYERS FL	4ESS 2nd Gen	(1998/1999)	
144	MONROVIA MD	4ESS 2nd Gen	(1998/1999)	
145	CHICAGO IL	4ESS 2nd Gen	(1998/1999)	
146	ATLANTA GA 	4ESS 2nd Gen	(07/1999)	Last #4ESS
147	CHICAGO IL (?)		N4E	2012?	
148	BOSTON MA (?)		N4E	?	
149	??? AZ (?)		N4E	?	Possibly replaced 140-T?
150	ATLANTA GA (?)		N4E	?	
151	??? FL (?)		N4E	?	Fort Myers/Naples area
152	GARDENA CA (?)		N4E	(08/2013)	Possibly replaced 130-T?
153	??? MA (?)		N4E	?	
154	DALLAS TX (?)		N4E	?	Possibly replaced 026-T?
155	??? AZ (?)		N4E	?	Phoenix metro (Scottsdale?)
156	SYRACUSE NY (?)		N4E	?	Possibly in addition to 096-T?
157	JACKSONVILLE FL (?)	N4E	?	Possibly replaced 041-T?
158	ANAHEIM CA (?)		N4E	?	Possibly replaced 004-T?
159	??? PA (?)		N4E	2016?	Possibly replaced 101-T?