NTP
                           NTP 297-1001-100                  PAGE 19
                          PREL., ISSUE 01D03
                               79 09 21



  10.   ABBREVIATIONS


  CC      - Central Control
  CCC     - Central Control Complex
  CCS     - One hundred call seconds per hour
  CDM     - Customer Data Modifications
  CMC     - Central Message Controller
  CPS     - Circuit Pack Storage
  CPU     - Central Processing Unit
  CSM     - Channel Supervision Message
  CDE     - Digital Carrier Equipment
  DCM     - Digital Carrier Module
  DMS     - Digital Multiplex System
  DNI     - Digital Network Interconnecting
  DP      - Dial Pulse
  DS      - Data Store
  DS1     - Primary digital  carrier, 24 channels, 1.544  Mb/sec bit
            rate
  I/O     - Input/Output
  IOC     - Input/Output Controller
  LM      - Line Module
  LME     - Line Module Equipment
  LMC     - Line Module Controller
  MAP     - Maintenance and Administration Position
  MF      - Multifrequency
  MFR     - Multifrequency receiver
  MIS     - Miscellaneous Equipment
  MS      - Message System
  MTC     - Magnetic Tape Center
  NET     - Network
  NM      - Network Module
  NMC     - Network Message Controller
  ODM     - Office Data Modification
  PCM     - Pulse Code Modulated
  PDC     - Power Distribution Center
  PM      - Peripheral Module
  PP      - Peripheral Processor
  PROTEL  - Procedure Oriented Typoe Enforing Language
  PS      - Program Store
  RAM     - Random Access Memory
  ROM     - Read Only Memory
  TM      - Trunk Module
  TME     - Trunk Module Equipment
  TTY     - Teletype
  VDU     - Visual Display Unit
  VF      - Voice Frequency
  TDM     - Time Divison Multiplex








                  DMS-100 FAMILY SYSTEM DESCRIPTION
                  (c) NORTHERN TELECOM LIMITED, 1978


                           NTP 297-1001-100                  PAGE 20
                          PREL., ISSUE 01D03
                               79 09 21



  TABLE_A


  o Frame        - Single  type of  frame for  use in  the core  and
  peripheral area

  Dimensions:    Width     27 in. (686 mm)

                 Depth     18 in. (457 mm)

                 Height    84 in. (2.1 m)


  o Shelf

  Provides 24 in. (610 mm) of usable space between its side plates.

  Dimensions:    Width     26 in. (660 mm)

                 Depth     12.5 in. (318 mm)

                 Height    35.6 cm (14 in.)

  o Ambient Temperature (~C)

  Normal:  10 to 30~C   Extreme:  5 to 49~C

  o Relative Humidity

  Normal:  20 to 50%    Extreme:  20 to 80%

  o Power

  Nominal: -48 volt battery power plant

                 Normal:  -49 to -53.5 volts

                 Extreme:  -44.75 to -55.8 volts

  Note:  Extreme conditions may exist for up to 72 hours.
















                  DMS-100 FAMILY SYSTEM DESCRIPTION
                  (c) NORTHERN TELECOM LIMITED, 1978


                           NTP 297-1001-100                  PAGE 21
                          PREL., ISSUE 01D03
                               79 09 21



                               TABLE_B


  o Call Capacity:    350,000 attempts per Average  Busy Season Busy
                      Hour (ABSBH)

  o Reliability:      Less than 2 hours downtime in 40 years.

  o Grade of
    Service           Local               ABSBH       10_HDBH   HDBH*

                      Dial tone delay >
                      3 secs              1.5% max    8%        20%

                      Originating
                      Matching loss (ML)  1.0% max

                      Incoming ML         2.0% max

                      Tandem ML           1.0%                  20%


                      Toll                          10HDBH    HDBH

                      Inc. digit
                      receiver delay                0.5%      2%

                      Tandem ML                     0.5%      2%

                      * High Day Busy Hour (HDBH)


























                   DMS-100 FAMILY SYSTEM DESCRIPTION
                   (c) NORTHERN TELECOM LIMITED, 1978



                             APPENDIX 1 TO                      PAGE 1
                            NTP 297-1001-100
                           PREL., ISSUE 01D03
                                79 09 21




  CALL DESCRIPTION DMS-100 (INTRA-OFFICE CONNECTION)


  1.01   The  main components of the  DMS switching system  and the
  means   by  which   they  communicate   are   described  in   NTP
  297-1001-100.  The way  that  these  components interact  in  the
  system is  described by following  an inter-office call  (line to
  line)  from  origination  to termination.  Figures  1  through  5
  illustrate  the  sequence  of   events  in  chronological  order,
  starting at the top of each figure.

  1.02   Refer to Figure 1.  Each line module (LM) has a Peripheral
  Processor (PP), which  continually scans the lines  in the module
  for a change of  state.  When the PP detects a  change of circuit
  state indicating an  OFF-HOOK, a message is sent  via the message
  channel to the Central Control (CC) informing it of the event.

  1.03    Upon receiving  the OFF-HOOK  message, the  CC assigns  a
  voice channel on  the speech link between the  originating LM and
  the network and assigns an integrity message to the calling line.
  The CC then  begins building a message for the  calling LM.  This
  consists of  a number of  commands, i.e., associate  the assigned
  voice channel with  the calling line, begin  sending and checking
  integrity, give  dial tone, start  receiving digits (assume  a DP
  -dial pulse- origination),  and report to the CC  after the first
  digit.  (Integrity  is  a  continuity  check  message,  which  is
  transmitted  over  the  voice channel.   If  a  discontinuity  in
  transmission of the integrity message is detected, the connection
  is automatically switched over to the other network plane.)

  1.04   When the first digit has  been reported, the CC determines
  the total number of digits required  (7 in this case).  A message
  is then sent to the calling LM to report after 7 digits. When the
  digits  have  been reported,  the  CC  translates the  digits  to
  determine the location of the called line.  Upon reception of all
  the necessary digits,  the CC sends a message  to the originating
  LM to stop receiving digits.

  1.05   Refer to Figure 2.  The  CC determines the location of the
  called line  and assigns a voice  channel on the speech  link bet
  called LM and the network.  It  then sets up a network connection
  in both planes between the calling and  called LM .  A message is
  sent to the called LM telling it  to stop looking for an OFF-HOOK
  on the  called line,  associate the  assigned voice  channel, and
  begin sending and checking integrity.  In  case the called LM has
  already reported an OFF-HOOK, the CC commands it to disregard the
  message.






                  DMS-100 FAMILY SYSTEM DESCRIPTION
                 (c) NORTHERN TELECOM LIMITED, 1978



                            APPENDIX 1 TO                    PAGE 2
                          NTP 297-1001-100
                         PREL., ISSUE 01D03
                              79 09 21




  1.06   When  the CC  receives a message  from both  LM indicating
  reception of  integrity, the  CC sends two  messages. It  sends a
  message to  the calling  LM to  start audible  ringing and  begin
  scanning for an ON-HOOK, and a message  to the called LM to start
  ringing the called line and begin sending the Channel Supervision
  Message (CSM) to  the calling LM .  [The CSM is a  digital signal
  multiplexed  over the  voice channel  which  reflects changes  of
  state (answer supervision).]

  1.07   Refer  to Figure 3.  When  the called line  goes OFF-HOOK,
  the CSM  signal changes state indicating  to the calling  LM that
  the  called line  has  gone OFF-HOOK.   The  calling  LM sends  a
  message to  the CC that  the called  party has answered.   The CC
  then sends a message to the called  LM to stop ringing the called
  line.  The two parties are now in the talking state.

  1.08   Refer to Figure 4.  Suppose the calling line goes ON-HOOK.
  The  calling LM  sends  an ON-HOOK  message to  the  CC.  The  CC
  responds with a message to both the  calling and the called LM to
  stop  sending  and  checking integrity.   When  the  CC  receives
  messages from both  LM indicating that integrity  is stopped, the
  CC releases the  network connection.  It then sends  a message to
  the called LM to release the  voice channel and start looking for
  an OFF-HOOK after the called party goes ON-HOOK. The same message
  is then sent to the calling LM.

  1.09   Refer to  Figure 5.  The disconnect  is handled similarly,
  when the called line goes ON-HOOK first.

























                  DMS-100 FAMILY SYSTEM DESCRIPTION
                 (c) NORTHERN TELECOM LIMITED, 1978



                            APPENDIX 2 TO                    PAGE 1
                          NTP 297-1001-100
                         PREL., ISSUE 01D03
                              79 09 21




  CALL DESCRIPTION DMS-200 (INTER-OFFICE CONNECTION)


  1.01   The  main components of the  DMS switching system  and the
  means   by  which   they  communicate   are   described  in   NTP
  297-1001-100.   The way  that these  components  interact in  the
  system is described by following an inter-office trunk connection
  from origination to termination.  Figures  1 through 4 illustrate
  the sequence  of events in  chronological order, starting  at the
  top of each figure.

  1.02    Refer  to  Figure  1.   Each  Trunk  Module  (TM)  has  a
  Peripheral Processor (PP)  which continually scans the  trunks in
  the module  for state changes. When  the PP detects a  seizure, a
  message is sent via the signalling channel to the Central Control
  (CC) informing it of the event.

  1.03   Upon receiving the seizure  message, the CC determines the
  trunk   group  type.   Suppose  the   originating   trunk  is   a
  Multifrequency (MF)  trunk.  The CC  then selects an  MF receiver
  (MFR), assigns   an integrity message  and voice channels  on the
  speech links between the MFR TM, and the network, and between the
  seized originating trunk TM and  the network.  The CC establishes
  a connection  in both network  planes between the  originating TM
  and the  TM associated with  the MFR (MFR  TM).  It then  sends a
  message to  both the originating TM  and MFR TM to  associate the
  voice channel and start sending and checking integrity.

  1.04    Refer  to   Figure   2.   Once   the   CC  has   received
  acknowledgement from both  TM that they are  receiving integrity,
  thus ensuring  that the  network connection  is complete,  the CC
  sends a  message to  the originating  TM to  send the  start dial
  signal to the originating office.   The received frequencies from
  the originating office are transmitted  over the voice channel to
  the MFR, where they are translated  into digits and stored in the
  MFR TM.  Upon reception and translation of all the digits the MFR
  TM sends the  digits via the message  channel to the CC.   The CC
  then sends a message to the originating TM and the MFR TM to stop
  sending and checking integrity.  Once  the TM have responded with
  messages indicating  that integrity is  stopped, the  CC releases
  the network connection.   The CC then sends a message  to the MFR
  TM to  idle the MFR receiver.  The CC translates the  digits from
  the MFR,  determines that  a terminating  trunk is  required, and
  then finds  an idle  trunk in  a trunk  group to  the terminating
  office.








                  DMS-100 FAMILY SYSTEM DESCRIPTION
                 (c) NORTHERN TELECOM LIMITED, 1978



                            APPENDIX 2 TO                    PAGE 2
                          NTP 297-1001-100
                         PREL., ISSUE 01D03
                              79 09 21




  1.05   Refer to  Figure 3.  The CC assigns  an integrity message,
  and  assigns a  voice  channel on  the  speech  link between  the
  network  and  the terminating  TM.   The  CC  sets up  a  network
  connection through  both network  planes between  the originating
  and  terminating  TM.    Two  messages  are  sent,   one  to  the
  terminating TM to associate the voice  channel, to send and check
  integrity, and to  send the CSM, the other to  the originating TM
  to send and check  integrity and to look for the  CSM.  When both
  TM respond with  messages confirming reception of  integrity, the
  connection through the office is complete.

  1.06   The CC then sends a message to the outgoing TM to send the
  seizure message to the  far end office and to look  for the start
  dial signal.   When the  terminating TM  receives the  start dial
  signal,  it sends  a message  to the  CC indicating  that it  has
  received it.   The CC  responds by  sending the  necessary digits
  over the message channel to the terminating TM.

  1.07   Refer to  Figure 4.  When a disconnect is  detected on the
  originating trunk, the TM sends a message to the CC. The CC sends
  a message to both TM to stop sending and checking integrity. Upon
  reception of messages from both  TM, indicating that integrity is
  stopped, the  CC releases the  network connection.  A  message is
  then sent to the outgoing TM to idle the outgoing trunk, followed
  by a message to the originating TM to idle the originating trunk.




























                  DMS-100 FAMILY SYSTEM DESCRIPTION
                 (c) NORTHERN TELECOM LIMITED, 1978