List of telephone switches explained

This list of telephone switches is a compilation of telephone switches used in the public switched telephone network (PSTN) or in large enterprises.

Alcatel

This lists Alcatel switches before the merger with Lucent Technologies.

1000 E10 / S12 (during the 1990s the E10 and S12 systems were converted into a single product line)
E10 versions:
- E10A (E10N3)- Original switch introduced in 1972 one of the earliest deployments of TDM switching in the world.
- E10B (E10N1)- Major revision in the 1980s which eventually saw ISDN capabilities. Common in France, Ireland, China, India and elsewhere.
- E10B3 - major revision in the 1990s. Common in France & Ireland
- OCB-283 - Another name for more modern versions of E10B and often the name used in India to distinguish it from older versions.
- E10-MT formerly Thomson MT-25 found mostly in France, and MT20 too.
- E10-Five E10B adapted for the North American environment as a class-5 switch.
- E10S satellite switching unit.
- E10-MSC mobile switching center for GSM and other protocols.
- 1000 (MM) E10 - Evolved switch for multimedia / broadband and IP network environments. Provides POTS/ISDN and next generation services.
S12 - Formerly known as "System 12" or the ITT 1240 or acquired by Alcatel when it purchased ITT's assets in Europe. This is a very widely deployed switching system found in Italy, Germany, Belgium, Australia and many other countries around the world. There are a large number of versions of this type of switch ranging from local, to transit to international gateway to mobile switching centers. The line was converted with the E10 family of exchanges.
OmniPCX Office
OmniPCX Enterprise

Thomson

MT-20^[2]
MT-25^[2]
MT-35^[2]

Automatic Electric Co.

Automatic Electric started producing electromechanical switching systems in the 19th century.

32A42
32A44
35E97
370A
370B
375A
375B
385A
385B
C1-EAX
CXP5
CXP5A
EAX #1
EAX #2
EAX #3
ESU 3072 Line
FW1 (Four Wire 1 Toll Switch)
GTD-3 EAX (Toll switch, NOT CCS7 capable although CCIS capable)
GTD-5 EAX (Class 5 switch, many in use today, was the primary switch in former GTE exchanges. Now supported by Lucent.)
GTD-120 Digital PABX
GTD-1000 Digital PABX
GTD-4600 Digital PABX
OMNI-S1 Digital PABX
OMNI-S2 Digital PABX
OMNI-S3 Digital PABX
Strowger Automatic Toll Ticketing (SATT); relay and type 45 rotary switch mechanics
Strowger Step-by-Step (Strowger patents were exclusively licensed to the Automatic Electric Company).
TSPS (Traffic Service Position System, obsolete system for operator handled LD calls.)
XPT No. 1
101 Director
OXO
OXE

Avaya

Currently Available Avaya Switches
- Application Server 5300 (AS5300)
- Communication Manager
- S8800
- S8730
- S8510
- S8400
- S8300D
- INDeX
- IP Office 500v2
Discontinued Avaya Switches
- 1A2 Key System (Electro-mechanical Key System made by Western Electric)
- DEFINITY BCS (Business Communications System)
- DEFINITY ECS (Enterprise Communications Server)
- DEFINITY G3R (RISC processor)
- DEFINITY Communications System Generic 2 (Formerly, System 85)
- DEFINITY Communications System Generic 3 (Formerly System 75)
- DIMENSION (Previously made by AT&T)
- G3MCC (Multi-Carrier Cabinet)
- HORIZON (Previously made by AT&T)
- MERLIN ("Classic"; 206, 410, 820. Originally made by AT&T)
- MERLIN PLUS ("Classic", Originally made by AT&T)
- MERLIN II ("Classic", Originally made by AT&T)
- MERLIN LEGEND
- MERLIN MAGIX, Integrated Communications System
- PARTNER
- PARTNER II
- PARTNER PLUS
- PARTNER ACS (Advanced Communications System), Replaced by IP Office 500 Partner Mode/Edition
- PARTNER Small Office Edition
- S8700 & S8720
- S8500
- S8300 a, b & c
- SPIRIT
- System 25 (Previously made by AT&T)
- System 75 (Previously made by AT&T)
- System 75 XE (Previously made by AT&T)
- System 85 (Previously made by AT&T)
- IP Office 400 (SOE, 403, 406, 406v2, 412), Replaced by IP Office 500

BPL Telecom

Sigma Indx-100
Sigma Indx-150
Sigma Indx-250
Sigma Indx-2000

GPO/PO/British Telecommunications

TXS
IAX5 Island Automatic eXchange No 5
SAX Small Automatic eXchange
UAX5
UAX6
UAX7
UAX8
UAX9
UAX10
UAX11
UAX12
UAX13
UAX14
UXE7
UXE8
TXK1
TXK5 (Ericsson ARM200)
TXK6 (Ericsson AKE)
TXE1
TXE2
TXE3
TXE4
TXE4A
TXE4E
TXE5
TXE6
System X
System Y (Ericsson AXE)
UXD5^[3]

CopperCom

CSX 1100
CSX 2100

Coral Telecom Ltd

IRIS IVDX Cloud
IRIS IVDX
IRIS Lite
IRIS NGX
DX-2000
SBDX

DGT

DGT3450

DIAX

Dikon ISDN switch^[9]

DSC Communications Corp.

DSC merged with Alcatel-Lucent

DEX 200
DEX 400
DEX 600
DEX 600E
DEX 600SC

Electronics and Telecommunications Research Institute (Korea)

The TDX switch was a joint project with Korea Telecom and four manufacturers, LG Electronics, Samsung Telecommunications, Daewoo Telecom and Hanwha Telecom.^[10]

TDX-1^[8] ^[11]
TDX-10^[8]
TDX-100 ^[8]

Ericsson

AGF
AKE
AR10
ARB (telex)
ARE11
ARE13
ARF10
ARF101
ARF102
ARK-D (decadic signalling)
ARK-M (mfc signalling)
ARK523 (small minor switching centre)
ARM20
ARM50
ARM 201
ARM202
ATE
ATE-NB
ATE-VB
AXE (spc electronic 1976)
AXE 10
- AXE 10 Remote
- AXE Local 7
- AXE Transgate
AXE810
Business Phone
- Business Phone Compact
- Business Phone 50
- Business Phone 128i
- Business Phone 250
CP-400 (crossbar)
CPP (Media Gateway)
MD110
MX-ONE
- MX-ONE Telephony Switch (TSW)
- MX-ONE Telephony Server (TS)
Rurax

Excel Switching

EXS 1000^[12]
EXS 2000^[12]
EXS 4000^[13]
EXS 8000^[14]
EXS 16000^[13]
EXS 30000^[13]
LNX 1000^[12]
LNX 2000^[12]

EFAR TELEKOM

MS26^[15]
MS38C
MS48C

Fujitsu

C140
C460
Focus I
Focus II
Focus III
Focus 50
Focus 100
Focus 196
Focus 960
Focus Elite
FETEX 100
FETEX 150
- FETEX 150 Local
- FETEX 150 Toll
Essence 630
Essence 650
9600 Series (Branded in Australia as Telecom 9600 series)
- 9600VS
- 9600S
- 9600M
- 9600L
Coral (branded as Fujitsu in Australia/New Zealand 1996–2002, manufactured by Tadiran Telecom)
- Coral FlexiCom 200 (formerly Coral SL, discontinued)
- Coral FlexiCom 300 (formerly Coral I, discontinued)
- Coral FlexiCom 400 (formerly Coral II)
- Coral FlexiCom 5000 (formerly Coral III)
- Coral FlexiCom 6000 (formerly Coral III)
- Coral IPx Office
- Coral IPx 500
- Coral IPx 800
- Coral IPx 3000
- Coral IPx 4000

Great Dragon Telecom (GDT)

HJD04 ^[16]

GEC

GEC later became Marconi (Britain)

SE50 (4000-type in GPO naming)

Hasler

List of the mainly electro mechanical switching systems from Hasler AG Bern, which were used in public telephone network in Switzerland for many decades. Hasler AG finally merged into Ascom in 1987.

HS 25 (modified from the Ericsson OL-100 system with double relays and 25-point selector (Ericsson license), mainly used for small villages and towns in the counties)
HS 31 (new developed register system, introduced in 1931, based on a new flat type relay and a 100-point two-motion selector, suitable for small and large exchanges)
HS 52 (new developed register system, introduced in 1953, based on a new 120-point selector, which was in fact a 4 x 30-point uniselector with 2 x 4 brushes offset by 180°, no zero position)
HS 52 A (new variant of HS 52 from 1973 with an almost full-electronic register evaluation unit called 'Umrechner', not processor based but centralized programmable by diode matrices)
HS 52 B (Processor controlled multiregister system with identifier, but the relay and selector based coupling stage was maintained from the original HS 52 system)
HS 68 (prototype of a semi-electronic switching system, based on adhesive reed-relays in the coupling stage. One sample system built but not pursued because of the arising PTT IFS-project)
AXE-10 (digital switching system from Ericsson, initially built and adapted for the Swiss market by Ascom Hasler under Ericsson license)

The last HS 52 A and B exchanges were in operation until the end of 1997. The personnel-intensive electro mechanical systems were shut down prematurely then, due to the imminent opening of the telecoms market in Switzerland. The last AXE-10 local subscriber were migrated to VoIP in June 2020.

Hitachi

EX10
HDX-10 ^[17]
DX
DX30
DX40
MDX
HCX5000

Huawei

C&C08 ^[18]

Hyundai Electronics Industries

HDX-300^[19]
HDX-2000^[8]

Indian Telephone Industries Limited

ESAX 200^[20]
ILT-512^[20]
ILT-2048^[20]
MILT-64^[20]

Inventel

ACT6000^[21]

Iskratel

SI2000^[22]
SI3000^[23]

Italtel

CT1
CT2
CIMA
UT10
UT20
TN16
UT100
iMSS (Italtel Multi Service Solution), a.k.a. i-SSW
i-VLS (Italtel Virtual Lite Switch)
i-MCS (Italtel Multimedia Communications Suite) - NGN Class 4 and Class 5 SoftSwitch + IMS Core + TAS for delivery of POTS/ISDN/SIP services over legacy and IP Broadband access type networks
i-RPS (Italtel Routing Policy Server) - Centralized Routing Platform for IP Convergent Networks

ITEC

EMS-1 (The ITEC Electronic Modular Switch is an electronic direct control switching system. The modules are combined to form a complete switch or any of the modules can be added to your present Step-by-Step Systems.)
EMS-2 (The EMS-2 RURAL SWITCH is a stored program control analog switch designed to be cost-effective in small exchanges. The modular design with connectorized cabling permits fast initial installation and growth. The system requires minimum maintenance and is particularly suitable for unattended exchanges. The EMS-2 distributed control design prevents total switch failure which could isolate a remote community.)
IDS (Integrated Digital System)

ITT Corporation (Includes ITT-Kellogg)

1210 (originally North Electric DSS)
1240
TCS5
TCS2
TE500A
TE400H
TE400
TD100
Kellex
7J
7X2
7X3
7XB
A1
A1-SPC
CRX
CSX
K60 (ITT-Kellogg)
K7 (ITT-Kellogg)
K1040
PC32B
Relaymatic (ITT-Kellogg)
TCS5
TRS4
AN/TTC-22 100 Line Automatic/Manual Military Tactical Switch (retired)

ITT (Europe)

7A, 7A1, 7A2, 7E (Rotary 'machine switching' system) driving system
7D (Rotary, for smaller/rural areas)
7B, 7B1 (Rotary, French adaptation)
6, 6N1, 6N2 (Rotary, French adaptation) step by step. Original R6 have not register
Pentaconta (crossbar)
Metaconta (SPC electronic)

JS Telecom

(Later Bosch Telecom)

JISCOS 8005^[24]
JISCOS 8007^[24]

KAREL

MS38^[25]
IPG Communication Platform
IPG1000/500
MS48C/128
DS200
IPS/400

Kvant-Intercom

Kvant (Квант)^[26]
Kvant-E (Квант-Е)^[26]

KD

XE30^[27]

Leich

All Relay (TPS, or terminal per station)
CS100
CS200
CX 2
CX 6
CX 90
LXP-2
LXP-3
LXP-4

LG Electronics

STAREX-TX1^[28]
STAREX-VK^[28] (VKX Ltd, Vietnam)

LONIIS

ATSC 90

Marconi (was GEC)

System X

Metaswitch

VP2510
VP3510
VP6010
CA9020
MG2510
MG3510

Mitel

TDM/Digital switches

SX5
SX10
SX20
SX50
SX100
SX200 D
SX200 Light
SX200 ML/EL/ELx
SX2000 SG
SX2000 S
SX2000 Light
GX5000L
GX5000S

Hybrid or IP-only switches

5000 Communications Platform (formerly Inter-tel 5000 CP)
SX200 ICP
3100 ICP
3300 ICP or Mitel Communications Director (MCD) MiVoice Business

Motorola

These are Mobile Telephone Switching Office Cellular switches

EMX2500
EMX4
EMX5000

NEC

Aspire
Topaz
C410
C460
NC10
NC23
NC100
NC23SE
NC230
NC400
NC460
NA820
NCA20
NCX23
ND10A
ND10B
ND20A
ND20B
ND20S
NEAX-61 (K, L, M & S)
NEAX-61E
- NEAX-61E Remote
NESXS (Nippon Electric step-by-step based on license from Western Electric)
M100
NEAX31 (Discrete Electronic CPU, 4-stage Crossbar switching fabric, PBX)
NEAX12 (Analog / Digital Hybrid PBX)
NEAX22 (Analog / Digital hybrid PBX)
NEAX 2000/1000
NEAX2400 (Fully Digital PBX)
XN120
NEC Univerge SL1000 (Small or Medium Sized, VoIP And TDM)
Enterprise IP Systems
- NEC Univerge SV7000 (Fully IP, VoIP and TDM) Pure IP Communication server
- NEC Univerge SV8100 (Fully IP, VoIP and TDM)
- NEC Univerge SV9100 (Fully IP, VoIP and TDM)
- NEC Univerge SV8300 (Fully IP, VoIP and TDM) Pure IP Communication server
- NEC Univerge SV8500 (Fully IP, VoIP and TDM) Pure IP Communication server
- NEC Univerge SV9500 (Fully IP, VoIP and TDM) Pure IP Communication server
- NEC Univerge 3C Pure IP Communication server

Nika (Ukraine)

ATSK50/200^[29]
ATSK100/2000^[30]

Nokia

DX 200
- DX 220
- DX 220 Compact
- IPA 2800

North Electric (Galion, Ohio)

CX "All-Relay Exchanges:

(CX evolved from the "Automanual" system designed by Edward Clements: "Clement eXchange" or "Community eXchange")

- CX30 (30 line)
- CX60 (60 line)
- CX100 (100 line)
- CX200 ("broadspan" up to 200 lines)
- CX1000 (large CX expandable to 10,000 lines)
MCX A version of the CX product line designed by F.R. McBerty after leaving Western Electric/Bell Labs and becoming President of North Electric.

The McBerty design used an early "wire spring relay" and welded piano wire interconnections rather than complex wire multiples. The system never achieved the reputation of the CX product due to problems with poor contact pressure in the interconnection relays. Despite its much lower cost of production and installation, the level of maintenance required to keep these systems on good order doomed this variation of the CX design.

DSS1 (North's first digital switch for local exchanges)

This later was renamed the ITT 1210 product upon purchase of North electric by ITT.

DSS2
ETS4 (Large #4A-ETS class toll switch based on Ericsson "code switch")
NTS4E (4-wire toll switch with Xbar switches and "Omni" processors)
NX1 (Family NX1A, B, C & D; All based on Ericsson By-Path Crossbar license)

L.M. Ericsson purchased North Electric in the early 1950s and brought this Swedish design to North where it was reworked to conform to U.S. telecommunications requirements.

- NX1D (Final production version)
- NX1E (NX-1D with OMNI Processor for line/directory, trunk and number-group translation services)

The NX-1E was not a SPC switch, rather it was a conventional path controlled switching matrix with electronic processors (computers) replacing the control, route selection and translation (directory number to line ID) functions.

NX2 (Family Small 90–1800 line CDO Xbar)
- NX2 (Original design 1959–1960)
- NX2A (Improved cabinets ~1962)
- UN2 Electrically and mechanically the same as the NX-2A but with design modifications specified by United Telecom (United Telecom/Sprint/Embarq) when they acquired North from L.M. Ericsson in the early 1960s. The "United" version of NX-2A replaced the intercabling connection blocks with wire wrap connections so that switches could be installed or expanded without having custom cable harnesses provided by North Electric.
- Switcher Family (NX-2A pre-installed in a trailer for rapid installation or portable/emergency use)
  - TSW Basic Unit with growth to ~360 lines
  - TSW2 Expanded unit with growth to ~1200 lines
  - TSW3 Jumbo unit with growth to system recommended maximums
TSD (toll switch)^[31]
AN/TTC-20 568 Line Military Fixed Switch (Used by US Air Force - only one was known in existence at Sembach AB, Germany) (retired)
AN/TTC-30 568 Line Military Tactical Mobile Switch (Used by US Army and Air Force) (retired)

Nortel

Application Server 5300 (AS5300)
Business Communications Manager (BCM)
- BCM50
- BCM200
- BCM400
- BCM450
Nortel Norstar Key Systems
- 308
- 616
- 824 Modular
- Norstar CICS (Compact Integrated Communication System)
- Norstar MICS (Modular Integrated Communication System)
Nortel Meridian 1 PBX
- Option 11/11E/11C
- Option 21/21C
- Option 51/51C
- Option 61/61C
- Option 81/81C
Communication Servers (CS Systems)
- CS1000 (22,500 lines 3200 trunks TDM and VoIP)
- CS1500 (48,000 lines 8,400 trunks TDM and VoIP)
- CS2000 Compact
- CS2000 (180,000 lines 200,000 trunks TDM and VoIP)
- CS2100 (230,000 ports, 125,000 IP phones, 150,000 analog telephones, 125,000 digital telephones, 200,000 IP trunks, 50,025 digital trunks, 32,000 analog trunks, 200,000 SS7 trunks, 4,093 H.323 gateways, 112,000 nodes per host, 99,999 ACD agents)
Digital Multiplex System (DMS)
- DMS-10 Carrier Class Switching System (320 ISDN PRI links or more than 20,000 lines) (First "production" class 5 digital switch installed in the North American public telephone network)
- DMS-10 RLCM (640 line remote)
- DMS-10 RSLE (520 line remote)
- DMS-10 RSLM (640 line remote)
- DMS-10S (super small DMS-10 for very small exchanges, less than 640 lines)
- DMS-10M (prepackaged DMS-10, a Community Dial Office in a pre-packaged container/"box")
DMS-100 FAMILY of Digital Exchanges
- DMS-100 (large local digital Class 5) (also known as an SL-100 when used as CPE (Customer Provided Equipment or PBX service)also known as Centrex.
- DMS-100/200 (local/toll digital more than 135,000 lines)
- DMS-200 (toll digital)
- DMS-250 (Equal Access Carrier Switch-digital)
- DMS-300 (International Gateway Switch-digital)
- DMS-300/250 (combination Carrier/International Gateway 70,000 to 100,000 trunks)
- DMS-500 (Local/Toll + CLEC Switch)
- DMS-Global Services Platform
- DMS-MTX (Cellular MTSO)
Stored Program (SP) (Electronic Stored Program Control using mini-bar switches)
- SP1 2-Wire (Local)
  - The SP1 processor was constructed using Small Scale Integration (SSI) Diode Transistor (DTL) Logic. Two types of memory was used. Processor read/write scratch memory (called CALL STORE) was implemented using a magnetic core variant called Ferrite Sheet. Program and Data Store (used to store Software and infrequently changed data) was implemented using a technology called piggy back twistor - in modern parlance a write once, read many times non-volatile memory system). As was the case with the #1ESS systems, processors and memory were duplicated with automatic comparison of processing results and automatic recovery in the event that a mismatch was discovered. It did not however support the complex recovery mechanism provided in the #1ESS where a processor from one half of the complex could be connected to a mix of memory (both call store and program store) modules from both halves of the complex in order to achieve a working combination. Processor diagnostics would generally narrow a problem down to a board or three. Connection was made via a crossbar switch.
  - A SP1 2-wire variant was also available that provided Centrex services.
  - A version of the SP-1 ESS that could provide both 2 & 4 wire services was also built. The first instance was installed in Vegreville Alberta in 1976 or 1977.
- SP1 4-Wire (Toll)
  - The first example of this switch was installed for Bell Canada, in Thunder Bay, Ontario in late 1973. It provided toll services for North Western Ontario and CAMA (Centralized Message Accounting) for the City of Thunder Bay. The City of Thunder Bay which operated its own Telephone Company installed a number of 2W SP1s.
- SP1E (used NT40 processor which was later the first processor system for the DMS-100 Family of switches)
NE-1ESS (Northern Electric version of Western Electric) #1ESS
- Bell Canada operated NE-1ESS 2 wire switches (some of which also provided Centrex services) in Toronto, Ottawa and Montreal. A 4W NE-1ESS was installed in Thunder Bay to provide telephone switching services (SAGE and AUTOVON)for USA and Canadian bases in that part of North America. The #1ESS was implemented using discrete diode transistor logic. A typical circuit board would implement a single 4 input "NAND" gate. Of the myriad of cards in the system - many were dedicated diagnostic gates. The diagnostic software had a very high (95% +) success rate identifying a single failing card. The success rate dropped quickly thereafter. Drifting Voltage Regulator cards caused a lot of angst.
NE-4A (Northern Electric version of Western Electric) 4A toll)
NE-5XB (Northern Electric version of Western Electric) #5Xbar)
SA1 (Small Northern designed crossbar CDO)
SA2 (Small Northern designed crossbar CDO)
SF1 (Small Northern designed crossbar CDO)
Norstar

Nortel Netaş (Turkey)

Elif I^[32]
Elif I I^[32]
DRX-4^[32]

NTT

D60^[27]
D70^[27]

Oki

Discovery I PBX
Discovery II PBX
Discovery III PBX
Discovery 8000 PBX
D10 ^[33]
D60 ^[34]
D70 ^[35]
KB270^[17]

Philips

UR
UR NB
UR49
URVB
UV
PRX/A
PRX/D
is3000 TDM PBX
SIP@Net Server Software PBX (owned by NEC)

ROLM

CBX (Versions 5,6,7000)
CBXII (Versions VS, S, M, L 8000–8004, VL 9000–9004)
9751 CBX (IBM co-design) 9004/9005 versions (Models 10, 20, 40, 50 and multinode 70)
9751-9006i (Version 1–6; Also called Models 30 and 80); Sold also as Siemens Hicom/HCM300
Redwood (limited key system)

Spetstroy-Svyaz

Proton-SSS^[36]

Pupin Telecom (Serbia)

DKTS 20^[37]
DKTS 30^[38]

REDCOM Labs

TRANSip
SLICE
HDX
IGX-A
IGX-MT
IGX-N
MDX 10K
MDX 384 modular exchange "stackable" to 384 lines/trunks

SAGEM

Eltex II (Telex)
Eltex V (Telex)

Samsung Telecommunications

S-1240^[8]
SDX-100
SDX-200^[8]
SDX-RB^[39]
TDX-1^[40]
TDX-1B^[40]
TDX-10^[40]

Siemens

SD50 PBX
SD192MX PBX
SD232 PBX
Saturn I PBX
Saturn II PBX
Saturn IIE PBX
Saturn III PBX
Hicom 100
Hicom 150/150E
Hicom 200 (Also sold as the ROLM 9200 CBX)
Hicom 300 (Also sold as the ROLM 9751-9006i CBX)
HiPath 3000
HiPath 4000
HiPath 5000
HiPath 8000
OpenScape SIP
No. 16 Step-by-Step
No. 17 Step-by-Step
No. 51 Step-by-Step
EDX-P
EMD55
EMD56
EMD57
ESK - CP24
ESK - CP44
ESK - CP44A
ESK 10000 E^[41]
EWSD
- Remote Switch Unit RSU-DE3
- Remote Switch Unit RSU-DE4
- Remote Switch Unit RSU-DE5
RCUB-800C
DCO-CS (Formerly Stromberg Carlson DCO) - Sold to Genband in 2006
HiQ8000
SPX2000 (Formerly Equitel)

Sonus

GSX9000
GSX4000
PSX6000
EMS 12000
Topcom 601
Topcom 200
Hicom 300

Stromberg-Carlson

DCO 21
DCO 80
DCO 200
DCO 360
Century DCO6000
- DCO Remote Line Switch 1000 (RLS 1000)
- DCO Remote Line Switch 4000 (RLS 4000)
- RLS 450
DCO-SE
DTM
ESC-1 "Crossreed" electronic exchange
- ESC-3
MS30
SC#5 (
1. 5 Crossbar
licensed from Northern Electric (Canada) for US sales/distribution)
Motorswitch - Siemens (Germany)
XY (Stromberg version of Ericsson "flat motion" switch operated in horizontal planes)

The DCO family starts as generic DCO

DCO
- DCO-E (Line Switch 10,000 lines)
- DCO-SE (Line Switch 10,000 lines, software enhanced, class features, centrex, etc.)
  - DCO-RLS (Remote Line Switch, controlled by hosts above)
    - RLS 1000 (Pedestal mount cabinet 1000 lines in a subdivision - required multiple T-1's to host)
    - RLS 4000 (Same thing, but 4000 lines)
    - RLS (This has the ability in a host outage to make intra-cabinet calls)
    - The line switches will also talk to AT&T SLC-96 pedestals – 96 lines on a ped
- DCO-CS (Long-distance, very limited lines – 1+ trunking to long-distance all T-1 cards)

Note: DCO systems are now supported by GENBAND

Tadiran Telecom

Coral FlexiCom 200 (formerly Coral SL, discontinued)
Coral FlexiCom 300 (formerly Coral I, Coral FlexiCom 400 (formerly Coral Idiscontinued)
I)
Coral FlexiCom 5000 (formerly Coral III)
Coral FlexiCom 6000 (formerly Coral III)
Coral IPx Office
Coral IPx 500
Coral IPx 800
Coral IPx 3000
Coral IPx 4000
Coral ICE
Coral Sea Soft Switch

Telesis IP Santral

Telesis IP Santral
Telesis Px24-Mrx
Telesis Px24N6 - Telesis Px24N7
Telesis Px24Mr6 - Telesis Px24Mr7* Telesis Px24Mr6
Telesis Px24Xr5

Telrad

TMX-10^[42]
TMX-100^[42]

TEMCCO (Iran)^[43]

National Digital Switch (B-NDS)^[44]
TEM X1000^[45]
TEM X256^[46]

Tesla

Step-by-Step

P51 (PSTN switch, modular design expandable from 100 to 10000 lines per exchange)
UTU (PBX, mechanical components identical to P51, but different signaling)
USTD (PBX especially designed for Czechoslovak Railways, with 4-wire long-distance stages)

Crossbar switch

PK 201 (PSTN Switch with R1 register signaling, not widely used)
PK 202 (PSTN Switch with R2 register signaling, very frequently used in 80's)
UK 101, UK 102 (PBXes up to 23 and 57 lines)
UK 111, UK 112 (PBXes of higher capacities, expandable to thousands of lines)

Tekelec

Tekelec 9000 Distributed Switching Solution (formerly SanteraOne)
Tekelec 7000 Class 5 Packet Switch (formerly Taqua Open Compact Exchange)

Tropico

Tropico C (Subscriber Line Digital Concentrator)^[47]
Tropico R (Small Capacity Local/Tandem Exchange)^[47]
Tropico RA (Local/Transit Exchange)^[47]

VEB Kombinat Nachrichtenelektronik

DVZ 2000^[48] (space-division digital switch)
ENSAD^[48] (time-division digital switch)
OZ 100 D^[48] ^[49] (96-line time-division digital switch)

Veraz Networks

Control Switch 5.8^[50]

VESNET

DRX-4^[51]

Vidar Corporation / TRW Vidar

IMA2
ITS 4
ITS 4/5
ITS 5

Western Electric / AT&T Technologies / Lucent

Panel

Local Panel
- Battery cut-off (BCO)
- Ground cut-off (GCO)
Panel Tandem
- Panel Sender Tandem
- Office Selector Tandem

Step-by-Step / Strowger

No. 1
No. 350A
No. 355A CDO (Community Dial Office)
No. 356A
No. 360A