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- ____________________________________________________________________________
- | |
- | "Peering into the Soul of ESS - The Master Control Center" |
- | |
- | Written By - Jack The Ripper |
- | |
- | Organized Crime (OC) |
- | Phile #2 of P/HUN Magazine Issue #5 |
- |____________________________________________________________________________|
-
-
-
- The Master Control Center is undoubtably the very essence of ESS. The
- Master Control Center (MCC) is the operational, maintenance, and administrative
- core of the electronic switching central office. This unit is what the ESS
- operators use to control the ESS switch. It test's customer lines and trunks,
- alarms to indicate malfunctions, perfroms system testing functions, controls
- operations, contains the magnetic tapes for recording Automatic Message
- Accounting (AMA) data, and contains various other specialized equipment.
-
-
- Primary Components of the MCC
- -----------------------------
-
- Master Control Console
- Trunk and Line Test Facilities
- Teletype (Teletypewriter) Channels
- AMA Recorders
- DATASPEED -40 Terminal with Display and Printer
-
-
-
- [---------------------------------------------------------------------------]
- [ Diagram of Processor Display Panel of Master Control Console in No.1A ESS ]
- [---------------------------------------------------------------------------]
- _______________________________________________________________________________
- | Processor Display | PS Bus | Pu Bus | CS Bus | AU Bus |
- | | Ad Re Ad Re| Ad Re Ad Re| Ad Re Ad Re| Ad Re Ad Re|
- -------------------------------------------------------------------------------
- |_____________________________________________________________________________|
- ||CC0 | ac| tr| po| st| of|| 0| 0| 1| 1|| 0| 0| 1| 1|| 0| 0| 1| 1|| 0| 0| 1| 1|
- ||----------------------------------------------------------------------------|
- || ltllh |====================================================================|
- ||-------|--------------------------------------------------------------------|
- || ltllh |====================================================================|
- ||____________________________________________________________________________|
- ||CC1 | ac| tr| po| st| of|| 0| 0| 1| 1|| 0| 0| 1| 1|| 0| 0| 1| 1|| 0| 0| 1| 1|
- ||----------------------------------------------------------------------------|
- || || || || || |
- || -------------------------------------------------------- |
- || |meno|kc || ||meno|kc || || |
- || |------------||___________||------------||___________||------------|
- || |02| |36|ntce|| 0! 0! 1| 1||02| |05|ntce|| 0| 0| 1| 1||fs|df|ft|df2|
- || -------------------------------------------------------------------|
- || | || || || |
- || | seno || || seno || |
- || | ---- ----|| || ---- ----|| |
- || |ps|0|2| |ii || ||ps|0|2| |lh || |
- || | ----- ----|| || ----- ----|| |
- ||----------------------------------------------------------------------------|
- || Update || OverRide Control || SysR || Processor Configuration Seq. |
- || || || || state counter |
- || ----- ||------------ -----||-----------||--------------- ----- |
- || |inp| ||bl|au|ps|cc| | no ||rea|ena|err||p3|p1|8|4|2|1|| |rec| |
- || ----- ||------------ -----||-----------||--------------- ----- |
- || ----- ||------------ || || |
- || |fs0| ||vr|a1|p2|c1| ||___________|| |
- || ----- ||------------ || || |
- || ----- || Activate|| ||Activate |
- || |fs1| || ---- ---- || ----- ||------ ------------------|
- || ----- || |x1| |x2| || |inv| ||q1|q2| |w1|w2|w3|w4|w5|w6|
- || || ---- ---- || ----- ||------ ------------------|
- || || || || |
- ||_________||__________________||___________||________________________________|
-
- Key
- ---
- w6 = Prssr Comfg
- w5 = Prgm Store
- w4 = Call Store
- w3 = Basic Prssr
- w2 = Reptd Pc
- w1 = Pc Atmpt
- x2 = Ovrd Efct
- x1 = Vrbl PS1
- q2 = Dsble Auto
- q1 = PC
- fs1 = FS 163
- c1 = CC1
- p2 = PS Bus 1
- a1 = AU Bus 1
- vr = Vrbl PS 0
- fs0 = FS 062
- rec = Reset Cntr
- p1 = Pmp 16
- p3 = Pmp 32
- err = Error
- ena = Enable Data
- rea = ready
- no = No Ovrd
- cc = CC D
- ps = PS Bus 0
- au = Au Bus 0
- bl = Blk 0 Ps 0
- inp = In Prgs
- SysR = System Reinitialization
- lh = LHIJI
- ii = IIOLI
- seno = Select No. (Select Number)
- df2 = Disk File 1
- ft = FS 1 Trbl
- df = Disk File 0
- fs = FS 0 Trbl
- meno = Member Number
- kc = K-Code
- || = Separates different Status Bars ie PS Bus, Processor Display, and Au Bus
- ac = Active
- tr = Trble
- po = Power
- st = Stop
- of = Offline
-
- +++ Added note on the key is that the abbreviations on the key are exactly the
- same as they appear on the panel.
-
-
- As you can see the MCC panel is divided up into five main groups of
- keys and lighted or LED displays; processor display, update, override control,
- system reinitialization, and processor configuration sequencer. The update
- group of keys and displays permits personnel to check when a program update is
- in progress. The override group of switchs and displays allows personnel to
- manually activate a central control unit, auxillary bus unit, and program store
- buse for emergency system recovery. The system reinitialization keys and
- displays allow personnel to manually reinitialize the system in conjuction with
- the override control or processor configuration sequencer group of keys.
-
- Workings of the MCC and Points of Interest
- ------------------------------------------
-
- Now that you have a little background information on the MCC, and are
- familiar with the MCC Console we can talk about the MCC a little more. The MCC
- can be used to remove from service all outgoing trunks, customer lines, and
- service circuits. This would be an interesting project next time your at your
- local CO to stop all service to an area. The MCC is capable of flagging
- pernament signals i.e. busy signal (black box on electromechanical or crossbar
- offices) . The master testing circuit can be connected to any outgoing trunk,
- service circuit, and most often any customers lines for testing purposes. Also
- the MCC can be connected to any voltmeter to test any customers line, service
- circuit, or outgoing trunk. The MCC also interacts with Remote Switching
- Systems to perform various testing functions to detect bad circuits and
- potential future problems i.e. a decaying circuit or two.
-
- AMA in the MCC
- --------------
-
- The Automatic Message Accounting recorder is located on the MCC and
- stores "customer billing information <right>" on magnetic tapes. One 2,400 ft
- reel of tape stores the billing data for 100,000 calls a day. These tapes
- however are backed up by duplicates to ensure against failure or billing error
- although it does happen, and the two copies are sent to a DPC (Data Processing
- Center) for analysis in computing customer bills The data that is to be
- stored is selected by the call processing program, which deceides whether or
- not the information for a call is to be stored. Then the data is temporarily
- stored in the AMA register (full capacity of the AMA register is 230 bits each)
- call store, and after completion of the call the related data is assembled in
- the BCD (Binary Coded Decimal (see Binary Number System for Decimal Digits
- Diagram)) format and placed in the AMA buffer call store.
-
- Binary Number System for Decimal Digits
- ---------------------------------------
-
- Decimal Four Digit Binary Code
- Number A B C D
- <8> <4> <2> <1>
- -----------------------------------------
- 0 0 0 0 0
- 1 0 0 0 1
- 2 0 0 1 0
- 3 0 0 1 1
- 4 0 1 0 0
- 5 0 1 0 0
- 6 0 1 1 0
- 7 0 1 1 1
- 8 1 0 0 0
- 9 1 0 0 1
- 10 1 0 1 0
- 11 1 0 1 1
- 12 1 1 0 0
- 13 1 1 0 1
- 14 1 1 1 0
- 15 1 1 1 1
-
- The recording procedure is then started by an AMA program in program
- store when the AMA buffer in call store is fully loaded. The AMA buffer has a
- full capacity of 140 words of 23 bits each. The AMA program will cause central
- control to direct that the data be transferred one word at a time to the AMA
- circuit for recording on the tape.
-
- Suggested Reading
- -----------------
-
- Basic Carrier Telephony, Third Edition by David Talley
- Basic Telephone Switching Systems, Second Edition by David Talley
-
- Anything Else by David Talley he wrote a few more. He is one of the best
- telecommunications authors, and all of this information was born into me
- through him. His books are also written with quesitons in the back which helps
- you to learn the information. Next time some moron throws an infoform at you
- asking what ESS is you can quite simply say something rude like, "Are you
- talking about the program interruptions in a No.1A ESS office which occur every
- 1.4 microseconds due to the system clock providing of course that it is running
- off of a 1A processor and hasn't been modified in any way, and is running stock
- software?" That outta get em eh?
-
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