| ==Phrack Inc.== |
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| Issue XIV, File 5 of 9 |
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| |_| Understanding the Digital Multiplexing System |_| |
| |_| Part II |_| |
| |_| |_| |
| |_| by Control C |_| |
| |_| |_| |
| |_| An Advanced Telecommunications, Inc. Production |_| |
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| DMS switches were first introduced in 1979. Since then it has been modified |
| to interface with numerous types of switches. DMS has the ability to |
| interface with SP-1, #5 XBar, 1ESS, 2ESS, 3ESS, 4ESS, NX1D, NX1E, TSD, SXS, |
| ETS4, NO. 1 EAC, NO. 2 EAX, NO. 3 EAX, TSPS, CAMA/3CL boards, Stromberg |
| Carlson Turret of ONI and Visual Indicators, Modified North Electric TSD for |
| ONI, Stomberg Carlson (CAMA operator Position - ONI/ANI), AE #31 Switchboard, |
| Co-located NT/AE switchboard I/C, O/G, UDC data poller of OM, DACS (Directory |
| Assistance Charging System), NT #144 LTD, WECO #14 LTD, WECO #16 LTD, CALRS |
| (Centralized Automated Loop Reporting System), Badger 612A, AE #1 and #21 LTD, |
| AE #30, SC #14 LTD, Lordel MITS70 line Test System, Porta System Line Test |
| Unit, Pulsar II IMTS, Teradyne loop test unit, and the WECO MLT 1 (Mechanized |
| Loop Testing System). |
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| Common Channel Interoffice Signaling |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| Common Channel Interoffice Signaling (CCIS) is a way of signaling and a way of |
| implementing network level services. CCIS provides reliable, crystal clear |
| data signaling links between the network and the switching offices. The CCIS |
| signaling method uses transmission equipment that is separate from voice |
| trunks. |
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| Common Channel Interoffice Signaling No. 6 |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| The basis for the CCIS system is the International Consultative Committee on |
| Telephone and Telegraph (CCITT) No. 6 international standard, which is brought |
| to its fullest capacity for use in the Stored Program Control (SPC) network of |
| AT&T. |
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| The CCIS6 network contains a bunch of signaling regions, each having a pair of |
| interconnected Signal Transfer Points (STP). The switching systems put into |
| CCIS6 that connect to STPs are called Serving Offices (SO). |
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| Band Signaling (CCIS-BS) is used on trunk signaling for intertoll-type trunks |
| using the CCIS network. |
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| Direct Signaling (CCIS-DS) is used for signaling between SPC switching |
| machines and a Network Control Point (NCP). At the present time, CCIS6 can |
| handle Enhanced INWATS Originating Screening Office (OSO), Calling Card |
| Validation (CCV), Mechanized Calling Card Service (MCCS), and Billed Number |
| Screening (BNS). CCIS6 is available with DMS-100/200, DMS-200, and |
| DMS-100/200 or DMS-200 with TOPS. |
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| CCIS6 Diagram: |
| NSB ST |
| ------------ - - - - - - - - - - - |
| DTC | | | ------- | |
| - - - DS30 | IPML | DS30 | - - - | || | | |
| --------| |------|- - - - - - |------|-| |---| || | | |
| Digital - - - | | | - - - | || | | |
| Trunks | | | | || | | |
| | | | ------- | |
| | | - - - - - - -|- - - - |
| DTC | | TM | |
| DIG - - - DS30 | NUC | DS30 - - - ----- |
| --------| |------|- - - - - - |--------| |----| | |
| ^ - - - |Network | - - - ----- |
| CCIS \ ------------ Modem |
| Signaling \ | |
| - - - ----- |
| AN Links--| | | CCC | |
| - - - ----- |
| Channel |
| Bank |
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| Acronyms: |
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| DIG - Digital |
| AN - Analog |
| DTC - Digital Trunk Controller |
| MSB - Message Switch Buffer |
| ST - Signaling Terminal |
| TM - Trunk Module |
| NUC - Nailed-Up Connection |
| IPML - Inter-Peripheral Message Link |
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| Common Channel Interoffice Signaling No. 7 |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| Common Channel Signaling (CCS) No. 7 or CCIS7 is a CCS system based on CCITT |
| No. 7. CCIS7/CCS7 on the DMS switch consists of two parts: the Message |
| Transfer Part (MTP) and the Interim Telephone user Part. They are compatible |
| with DMS-100, DMS-200, DMS-100/200, and DMS-100/DMS-100/200 with TOPS. |
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| CCIS7 can't tell the difference between banded and direct signaling. CCIS7 |
| uses Destination/Origination Point Codes (DPC/OPC) to route back to the |
| switch. |
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| CCIS7 can handle Automatic Calling Card Service (ACCS), Enhanced INWATS, Local |
| Area Signaling Services, and Direct Service Dialing Capabilities. |
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| Equal Access |
| ~~~~~~~~~~~~ |
| The DMS-200 Access Tandem (AT) gives a traffic concentration and distribution |
| function for interLATA traffic originating and a distribution function for |
| interLATA traffic origination or terminating inside a Local Access and |
| Transport Area (LATA). This gives the interLATA Carrier (IC) access to more |
| that one end office inside the LATA. It can handle InterLATA Carrier access |
| codes (10xxx), 10xxx and 950-yxxx dialing, Automatic Number Identification |
| (ANI) on all calls, answer supervision, equal access Automatic Message |
| Accounting (AMA) for both originating and terminating calls, and operator |
| service signaling. |
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| The DMS-100 EA gives direct and tandem switched access service inside the LATA |
| for originating and terminating to interLATA Carriers. It is available in the |
| following three ways: |
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| Equal Access End Office (EAEO) |
| ------------------------------ |
| DMS-100 Equal Access End Office (EAEO) gives a direct interconnection to |
| interLATA Carriers' (IC) and international Carriers' (INC) Points of Presence |
| (POP) inside the LATA. |
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| Access Tandem with Equal Access End Office |
| ------------------------------------------ |
| The DMS-200 Access Tandem (AT) when used with equal access end office (EAEO) |
| lets trunk tandem interconnect to ICs/INCs POP inside the LATA. |
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| The connection of the Equal Access End Office (EAEO) to an IC/INC through the |
| DMS-200 Access Tandem (AT) uses what is called two-stage overlap output |
| pulsing which makes the time it takes to set up a call quicker. The AT uses |
| the digits OZZ + XXX out pulsed in the first stage to identify the IC/INC |
| dialed and to pick out outgoing trunk. Then a connection is established from |
| the IC/INC to the EAEO through the AT. The second stage digits consist of ANI |
| and the called numbers are passed through the DMS-200 AT at the IC/INC. |
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| An AMA terminating record in AT&T format is produced by the DMS-200 for all |
| the EAEOs. A per call terminating AMA record is made for calls that get to |
| the stage where the trunk from the IC/INC has been seized and a "wink" has |
| been returned by the DMS-200 AT. |
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| Access Tandem with a Non-Equal Access End Office |
| ------------------------------------------------ |
| DMS-200 AT using a non-equal access end office gives trunk tandem connection |
| to an IC/INC POP within the LATA. To set up a call, connection of Feature |
| Group B (FGB) or Feature Group C (FGC) End Office to an IC/INC through the |
| DMS-200 AT uses the standard Bell Central Automatic Message Accounting (CAMA) |
| signaling. The Access Tandem uses the XXX digits of the access code 950-YXXX |
| out pulsed from the FGB end office to identify the IC/INC and to connect to an |
| outgoing trunk. |
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| Mechanized Calling Card Service (MCCS) |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| The fraudulent use of calling cards, third number and collect calls and the |
| increasing movement to automate current operator services has directly led to |
| the implantation of the Mechanized Calling Card Service (MCCS) to DMS-200/TOPS |
| and to the remote and host Operator Centralization (OC). |
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| MCCS uses CCIS to relay queries and responses to and from the DMS-200/TOPS. |
| Operator handled calling card calls and the direct entry by subscribers of |
| Calling Cards by DTMF (Touch-Tone) telephones are given special provisions by |
| the MCCS. Both the operator handling and the direct entry of calling card |
| calls are decreasing the size of the operators. |
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| Billed Number Screening (BNS) gives an enhancement to the operator-handled |
| collect and third-number billing by using CCIS to screen a number at the |
| billing validation data base for billing restrictions (i.e. the third number |
| is a fortress). This feature naturally will reduce fraudulent use of the |
| collect call feature. |
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| Common Channel Interoffice Signaling-Direct Signaling (CCIS-DS), which is |
| the feature that the MCCS is designed around, is used to transmit messages to |
| and from many possible Billing Validation Centers (BVCs). Messages |
| transmitted to the BVC about MCCS include the billing number and the Personal |
| Identification Number (PIN). In BNS the messages have the special billing |
| number (collect or third number). The return messages from the BVC include |
| validity (of the number), billing restrictions (if any), and the Revenue |
| Accounting Office (RAO) code. |
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| Auxiliary Operator Services System |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| The DMS-200 Auxiliary Operator Services System (AOSS) is used primarily for |
| Directory Assistance and the intercept needs that are not included in the TOPS |
| package. The AOSS is similar to TOPS and co-exists with TOPS on the DMS-200 |
| Toll system. |
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| Major benefits of the AOSS include: Directory Assistance is provided with a |
| modern environment, AOSS position administrative activities are performed by |
| the DMS-200 toll maintenance system, trunking savings are achieved by |
| combining trunking for 1+, 0+, and Directory Assistance traffic, DA services |
| are managed by using TOPS methods, creation of a built-in training system |
| which does not require additional training equipment and reduces training |
| costs. |
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| Integrated Business Network |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| The Integrated Business Network (IBN) is a revenue-producing concept designed |
| for small and big businesses to offer modernized PBX and Centrex features. |
| The Operating Company can use the IBN to maintain and enhance its competitive |
| position on a operational DMS-100 and DMS 100/200 switches. While using the |
| DMS-100 switch, the Operating Company can support varying business features |
| along with existing local/toll traffic. |
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| IBN services can be introduced to a Centrex-Central Office (CO) or a |
| Centrex-Customer Unit (CU) by additional software modules and minor hardware |
| enhancements. |
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| Current IBN features include: A growing system that can handle 30,000 lines, |
| networking capabilities, city wide service for DMS-100 switch and remotes for |
| any one customer Station Message Detail Recording (SMDR), which gives IBN |
| customers call records. The records can be used for system analysis and |
| control and station charge-back. SMDR can use LAMA records (if the IBN host |
| has LAMA equipment), centralized attendant maintenance, and administration |
| functions and Direct Inward Dialing (DID). |
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| Electronic Switched Network (ESN) |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| The Electronic Switched Network is designed to meet the telecommunication |
| needs of large multi-location corporations. The ESN is made up of a SL-1 or |
| SL-100 Digital Business Communications System with networking features or a |
| DMS-100 IBN host. The SL-1 can handle from 30-5000 lines. The SL-100 and the |
| DMS-100 IBN hosts can hold from a few thousands to 30,000 lines. |
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| A DMS-100 IBN or SL-100 can remotely serve many locations from the host site. |
| This is done by a connection through digital transmission facilities which are |
| set up at remote modules at the subscriber's premises. |
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| Here are some diagrams showing the differences between normal private |
| telecommunications networks and ESN networks. |
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| Normal telecommunications network |
| ================================= |
|
|
| ----- ------ |
| [Phone]--| SnS | | SL-1 |-[Phone] |
| | PBX | | PBX | |
| ----- ------ |
| | |DOD/DID DOD/DID| | |
| | ------- ------- | |
| |Tie | | Tie| |
| |Trunk --------- Trunk| |
| ------| Class-5 |------ |
| ----| Centrex |---- |
| | --------- | |
| | | |
| | | |
| | | |
| ----- Tie Trunk --------- |
| | SnS | ----------| Class-5 | |
| | PBX | | Centrex | |
| ----- --------- |
| | | |
| | | |
| | | |
| | | |
| ------- ------ |
| [Phone]-| Small | | SL-1 |-[Phone] |
| | PBX | | | |
| ------- ------ |
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| ESN Network |
| =========== |
| -------- ---------- |
| [phone]--| Remote | | SL-1 PBX |--[phone] |
| | Module | | ESN Main | |
| -------- ---------- |
| | | |
| | DS-1 Facility | DS-1 Facility |
| | -------------- | |
| --------> | Local Class 5| <--------- |
| [phone]---------| DMS-100 | |
| ----| IBN/ESN |------------- |
| 2W Loop MFIDP | -------------- | ESN Trunk Group |
| or DS-1 | | | or DS-1 |
| | ----- --------------- |
| | | CSC | | Local Class 5 | |
| -------- ----- | DMS-100 | |
| | SL-100 | <--- DS-1 ----> | IBN/ESN | |
| -------- Facility --------------- |
| | | |
| | | |
| | DS-1 Facility | DS-1 Facility |
| | | |
| -------- ---------- |
| [phone]--| Remote | | SL-1 PBX |--[phone] |
| | Module | | ESN Main | |
| -------- ---------- |
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| Specialized Common Carrier Service (SCCS) |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| The DMS-250 Specialized Common Carrier Service (SCCS) provides the capability |
| of Analog to Digital (A/D) and Digital to Analog (D/A) conversions which are |
| necessary with analog circuits. The DMS-250 can also switch voice and data |
| circuits. |
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| The DMS-250 takes either analog or digitally encoded info and by using time |
| slot interchange, switches it from any input port to a temporary addressed and |
| connected exit port. The info may or may not be converted back to analog. |
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| Cellular Mobile Radio Service |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| A cellular system consists of two main parts: a cellular switch and cell site |
| equipment. |
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| Cellular Switching Systems |
| ~~~~~~~~~~~~~~~~~~~~~~~~~~ |
| A cellular switch performs three main functions: audio switching, cell site |
| control, and system administration. |
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| The DMS switches provide three basic implementations for cellular switching: |
| Stand-alone, Combined, and Remote. |
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| Stand-alone switching is done by a Mobile Telephone Exchange (MTX) which is |
| interfaced with one or more class 5 end offices. The connection is made by |
| DID/DOD trunks. Depending on the needs of the area, the MTX can be divided as |
| follows: MTX which serves urban areas, MTXC which handles suburban areas, and |
| MTXM which is used for rural areas. |
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| Combined switching is incorporated into a DMS-100 by some hardware additions |
| and cellular software. Combined switching is designed to give an easy, |
| cost-effective way to install cellular services to an existing host. |
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| Remote Switching is done by combining Remote Switching Center (RSC) with a |
| Cell Site Controller (CSC). This combination is hosted by either a |
| stand-alone or a combined switch. Remote Switching is designed for serving |
| suburban centers, remote areas, or a small community and it gives extra |
| flexibility for a growing system. |
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| All of these cellular switches have the ability to balance the workload among |
| various cell sites. For example, if one site's workload reaches the |
| programmable level of congestion, calls would be routed to nearby sites that |
| can handle the extra calls. |
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| Cell Site Equipment |
| ~~~~~~~~~~~~~~~~~~~ |
| Cell site equipment consists of a CSC and radio equipment. The CSC is |
| controlled by the cellular switch and it controls radio equipment and |
| maintenance tasks. The CSC will work on any MTX cellular switch because of |
| the Remote Cluster Controller (RCC). |
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| The radio equipment consists of self-contained Radio Channel Units (RCU), |
| antennas, transmitter multi-couplers, and receiver combiners. |
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| By different program software, an RCU can perform voice, control locating, and |
| test functions. The self contained nature allows the RCU be remotely located |
| to the CSC. A RCU has built-in circuitry for extended testing of the radio |
| part of the system. |
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| Control C |
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| <End of File> |
| <May 1987> |
| ______________________________________________________________________________ |
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