Nortel DMS-100 General Description Manual

297-1001-131

DMS-100 Family

DMS-100 Ringing System

General Description

BASE15 and up Standard 06.01 October 2000

DMS-100 Family

DMS-100 Ringing System

General Description

Publication number: 297-1001-131
Product release: BASE15 and up
Document release: Standard 06.01
Date: October 2000

Copyright © 1990, 1991, 1993, 1994, 1995, 1996, 1998, 1999, 2000 Nortel Networks,
All Rights Reserved

NORTEL NETWORKS CONFIDENTIAL: The information contained herein is the property of Nortel Networks and is

strictly confidential. Except as expressly authorized in writing by Nortel Networks, the holder shall keep all information contained
herein confidential, shall disclose the information only to its employees with a need to know, and shall protect the information, in
whole or in part, from disclosure and dissemination to third parties with the same degree of care it uses to protect its own
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holder is granted no rights to use the information contained herein.

Nortel Networks,the Nortel Networks logo,the Globemark, How the World Shares Ideas, and Unified Networks aretrademarks of
Nortel Networks.

Publication history

October 2000

BASE15 Standard 06.01

• Added Universal Edge 9000 (UEN) ringing information.

March 2000

BASE14 Standard 05.01

• Added United Kingdom ringing configuration changes

September 1999

BASE12 Standard 04.04

• added a ringing generator configuration change procedure for single line
concentrating module configurations

August 1999

BASE12 Standard 04.03

iii

• changed description of Japan ringing type C3D from feature AU3458

• included an illustration of United Kingdom distinctive ringing cadences

• added a ringing generator configuration change procedure

DMS-100 Family DMS-100 Ringing System BASE15 and up

iv

July 1998

August 1997

August 1996

August 1995

BASE08 Standard 04.02

• added description of United Kingdom ringing and a limit on Distinctive
Ringing Enhancements

BASE08 Standard 04.01

• added C3C distinctive ringing pattern information for Malaysia and
Australia from feature AR2137

• updated descriptionof revertiveringing, noting thatrevertive ringingis not
supported for FSR lines

BCS36 Standard 03.05 incorporated editorial changes

BCS36 Standard 03.04 incorporated editorial changes

April 1995

December 1993

BCS36 Standard 03.03

• added note in chapter 1 for setting office parameters
IMMEDIATE_RING_ENABLE and
ALLOW_RINGING_ON_TIP_SIDE with regard to immediate ringing
functionality.

• added information about response to the QUERYPM command at the
MAP terminal for LCMs when in no-display mode. The switch provides
operating company personnel the status of the ringing generators in a
posted LCM.

BCS36 Standard 03.02

• incorporated editorial changes

• removed low-level software descriptions of ringing functionality

297-1001-131 Standard 06.01 October 2000

October 1993

BCS36 Preliminary 03.01

• rearranged chapters

• incorporated technical and editorial changes

• updated section on LCMs in chapter 3.

March 1991

BCS32 Standard 02.01

• included streamline information

• converted document to new format

September 1990

BCS31 Standard 01.07

• added NT2X27AE ringing generator interface (RGI) to the list of RGIs in

v

the Line Module/Remote Line Module description.

• added statement indicating that an NT2X27AB is required when using
CODED C30 ringingand an NT2X27AA is required whenusing CODED
C ringing.

DMS-100 Family DMS-100 Ringing System BASE15 and up

Contents

About this document xi

1 DMS-100 ringing overview 1-1

vii

When to use this document xi
How to check the version and issue of this document xi
References in this document xi
What precautionary messages mean xii
How commands, parameters, and responses are represented xiii

Input prompt (>) xiii
Commands and fixed parameters xiii
Variables xiii
Responses xiv

Introduction 1-1
Normal and immediate ringing 1-2
ANI and coin functions 1-5
Types of ringing 1-5

Frequency selective ringing 1-5
Superimposed ringing 1-9
Coded ringing 1-15
Distinctive ringing 1-20
Ringing characteristics 1-32
Provisioning ringing generators 1-39
Ringer configurations 1-39
Audible ring back signal 1-41

Ringing in the UEN 1-42

2 Ringing in Series I peripherals 2-1

Ringing types supported by LM and RLM 2-1
LM and RLM ringing configuration 2-1
LM and RLM ringing hardware 2-2

LM and RLM ringing process 2-3
SP and RGI interactions 2-5

Ring generator interface 2-2
Line module power converter 2-3
Ring multiplexer 2-3
Ring bus 2-3

LM and RLM processors associated with ringing 2-4
Ringing takeover 2-6

Ringing take back 2-7

DMS-100 Ringing System

viii Contents

Ringing generator capacity 2-8
Ringing generator takeover and take back 2-9

LM and RLM ringing generator parameters 2-9

3 Ringing in Series II peripherals 3-1

Ringing in the subscriber carrier module 3-1

SCM-100U 3-1
SCM-100U/RCU ringing configuration 3-2
Ringing hardware 3-3
SCM-100R 3-5
SCM-100R/RCT ringing configuration 3-5
Ringing hardware 3-7
SCM-100R ringing hardware 3-7
RCT ringing hardware 3-8
Ringing generator capacity 3-9
Ringing generator takeover 3-9

SCM-100S 3-9

Ringing types supported by SCM-100S 3-9
SCM-100S ringing configuration 3-9
SCM-100S ringing hardware 3-10
RCS hardware 3-11
Ringing generator takeover 3-11
LCM ringing functional description 3-11
Ringing generator capacity 3-14
Types of ringing supported 3-14
Ringing configuration 3-14
Detailed ringing schematic 3-17
Ringing signals 3-19
ANI/coin signals 3-21
Ringing process 3-22
Ringing synchronization task 3-22
Ringing generator output zero-crossing detection 3-22
Ringing schedule task 3-22
Ringing and ANI/coin messaging 3-23
Ringing sequence flowchart 3-24

Ringing generator configuration change procedure 3-26

Dual LCM configuration 3-26

Single LCM configuration 3-37
Ringing in the Universal Edge 9000 3-45
Ringing in the Remote Line Concentrating Module 3-47
Ringing in the Outside Plant Module and OPAC 3-47
Ringing in the Remote Switching Center 3-47

4 Administration of DMS ringing 4-1

Assigning ringing to line modules 4-1

297-1001-131 Standard 06.01 October 2000

Assigning ringing type to PM 4-1

Ringing generators 4-2

Ringing generator interface 4-2

Line cards 4-2

Table LMRNG 4-3

Assigning ringing to line concentrating modules 4-3

Setting up the LCM or RLCM ringing generators 4-3

Line cards 4-4

Table LCMINV 4-4
Assigning ringing to SCM-100R 4-4

Ringing generators 4-4

Line cards 4-5

Table RCTINV 4-5
Assigning ringing to SCM-100S 4-5

Ringing generators and line cards 4-5

Table RCSINV 4-5
Assigning ringing to SCM-100U 4-6

Ringing generator 4-6

Line cards 4-6

Table RCUINV 4-6
Assigning ringing to the OPM 4-6
Assigning ringing to the RSC 4-6
Assigning ringing to lines 4-6
Setting immediate ring enable 4-7
Revertive ringing 4-7
Teen ringing tables 4-7
Distinctive ringing tables 4-7

Table OFCOPT 4-7

Table CUSTSTN 4-7

Table LMRNG 4-8

Table LCMINV 4-8

Contents ix

5 Ringing system maintenance 5-1

Ringing user interface 5-1
Ringing generator overload control 5-1

RG overload control - Series I peripherals 5-1

RG overload control - Series II peripherals 5-2
Troubleshooting 5-2

Log reports associated with ringing 5-2

Ringing generator status 5-5

Ringing generator alarms 5-6

Replacing ring generators 5-6

Ringing maintenance and troubleshooting 5-6

DMS-100 Ringing System

About this document

When to use this document

This document describes the DMS-100 ringing system. It is intended as a
general reference for operating company personnel responsible for
engineering, administration,and maintenanceof the DMS-100ringing system.

How to check the version and issue of this document

The versionand issue of thedocument are indicated by numbers,for example,

01.01.
The first two digits indicate the version. The version number increases each

time the document is updated tosupporta new software release. For example,
the first release of a document is 01.01. In the next software release cycle, the
first release of the same document is 02.01.

The secondtwo digitsindicate theissue. The issuenumber increaseseach time
the document is revised but rereleased in the same software release cycle. For
example, the second release of a document in the same software release cycle
is 01.02.

xi

To determine which version of this document applies to the software in your
officeand how documentationfor your product isorganized, check therelease
information in Product Documentation Directory, 297-8991-001.

This document is written for all DMS-100 Family offices. More than one
version of this document may exist. To determine whether you have the latest
version of this document and how documentation for your product is
organized,check therelease informationinProductDocumentation Directory,
297-8991-001.

References in this document

The following documents are referred to in this document:

• Product Documentation Directory, 297-8991-001

• Subscriber Carrier Module-100 Rural General Description,
297-1001-064

DMS-100 Family DMS-100 Ringing System BASE15 and up

xii

• DMS-100 Provisioning Manual, 297-1001-450

• Peripheral Modules Maintenance Guide, 297-1001-592

• SMS Maintenance Manual, 297-8231-550

• SMU Maintenance Manual, 297-8241-550

• Hardware Description Manual, 297-8991-805

• DMS-1 Urban System Description, 363-2051-100

• DMS-1 Urban Circuit Pack Description, 363-2051-101

• SERVORD Reference Manual

• Office Parameters Reference Manual

• Log Report Reference Manual

• Translations Guide

• Card Replacement Procedures

• Customer Data Schema Reference Manual

What precautionary messages mean

The types of precautionary messages used in NT documents include danger,
warning, and caution messages. Danger, warning, and caution messages
indicate possible risks.

Examples of the precautionary messages follow.

DANGER

Possibility of personal injury

DANGER

Risk of electrocution

Do not open the front panel of the inverter unless fuses F1,
F2, and F3 have been removed. The inverter contains
high-voltage lines. Until the fuses are removed, the
high-voltage lines are active, and you risk being
electrocuted.

297-1001-131 Standard 06.01 October 2000

WARNING

Possibility of equipment damage

DANGER

Damage to the backplane connector pins

Align the card before seating it, to avoid bending the
backplane connector pins. Use light thumb pressure to
align the card with the connectors. Next, use the levers on
the card to seat the card into the connectors.

CAUTION

Possibility of service interruption or degradation

CAUTION

Possible loss of service

Before continuing, confirm that you are removing the card
from the inactive unit of the peripheral module.
Subscriber service will be lost if you remove a card from
the active unit.

xiii

How commands, parameters, and responses are represented

Commands, parameters, and responses in this document conform to the
following conventions.

Input prompt (>)

An input prompt (>) indicates that the information that follows is a command:

>BSY

Commands and fixed parameters

Commands andfixed parametersthat are enteredat aMAP terminal areshown
in uppercase letters:

>BSY CTRL

Variables

Variables are shown in lowercase letters:

>BSY CTRL ctrl_no

The letters or numbers that the variable represents must be entered. Each
variable is explained in a list that follows the command string.

DMS-100 Family DMS-100 Ringing System BASE15 and up

xiv

Responses

Responses correspond to the MAP display and are shown in a different type:

FP 3 Busy CTRL 0: Command request has been submitted.

FP 3 Busy CTRL 0: Command passed.

The following excerpt from a procedure shows the command syntax used in
this document:

1 Manually busy the CTRL on the inactive plane by typing

>BSY CTRL ctrl_no

and pressing the Enter key.

where

ctrl_no

is the number of the CTRL (0 or 1)

Example of a MAP response

FP 3 Busy CTRL 0: Command request has been submitted.

FP 3 Busy CTRL 0: Command passed.

:

297-1001-131 Standard 06.01 October 2000

1 DMS-100 ringing overview

Introduction

The DMS-100 ringing system performs automatic number identification
(ANI) and coin functions and supports the following three ringing systems
used in North America:

• Bell Canada

• Bell operating company (BOC)

• Rural Electrification Association (REA)

The DMS-100 ringing signal is based on a 6-second (s) cycle. The cycle is
dividedinto 12time slots,which are thesmallest divisions ofthe ringingcycle.
The duration of each timeslot is software controlled and is typically set to0.5
s. In many DMS-100 peripherals, the ringing cycle is further divided into
larger divisions consisting of one or more time slots.

The DMS-100 line module equipment (LME), line concentrating equipment
(LCE), and Subscriber Carrier Module (SCM) each use a distinctive ringing
cycle format. For example, each subdivides the ringing cycle differently.

1-1

The ringing cycle in the LMEis divided into12 time slots, which aretypically
set to 0.5 s each. The ringing cycle in the Line Concentrating Module (LCM),
like the LME, is also divided into 12 time slots. However, the LCM ringing
cycle is further divided into four subcycles. The subcycles consist of one or
more time slots.

The ringing cyclein the SCM, like theLME and LCM, is dividedinto 12 time
slots. It is further subdivided into three phases consisting of four time slots of
2 s each.

A diagram of each of the DMS-100 ringing cycle formats is shown in the
following figure.

DMS-100 Family DMS-100 Ringing System BASE15 and up

1-2 DMS-100 ringing overview

Figure 1-1 Illustration of a DMS-100 ringing cycle

(500 milliseconds[ms])

LME ringing cycle

Ringing cycle

(6 s)

Time slot

0

12

Time slot
(500 ms)

0

12

Subcycle

0123

Time slot
(500 ms)

0

12
Phase 1 Phase 2 Phase 3

34 5 6 7 891011

LCE ringing cycle

Ringing cycle

(6 s)

3456 7891011

Subcycle Subcycle Subcycle

SCM ringing cycle

Ringing cycle

(6 s)

3456 7 891011

Note: The time slot duration for LCE ringing varies with the ringing
scheme. If ringing issuperimposed or coded, all time slot durations are500
ms. If frequency selective ringing (FSR) is used, time slot 0 is 60 ms, time
slot 1 is 65 ms, time slot 2 is 75 ms, and the remainder of the time slots are
45 ms each. The total duration for the ringing cycle remains 6 s.

Operating company personnel can define the time slot and subcycle durations
according to the type of ringing scheme being used.

Normal and immediate ringing

The DMS-100 switch applies power ringing to a line in either normal or
immediate ringing mode. In the normal ringing mode, the DMS-100 switch

297-1001-131 Standard 06.01 October 2000

DMS-100 ringing overview 1-3

applies power ringing at the start of the next available ringing cycle. If power
ringing can not be applied during the first time slot of a ringing cycle, the
DMS-100 switch will try to schedule power ringing during the first time slot
of the next ringing cycle. This can cause delays in power ringing of up to 6 s
in LCMs and up to 8 s in line modules (LM). To reduce these delays, an
immediate ringing mode is available.

In the immediate ringing mode, the DMS-100 switch applies power ringing
during the next available time slot of the ringing portion of the ringing cycle.
If power ringing cannot be applied during the first time slot of the ringing
portion of a ringing cycle, the DMS-100 switch will try to schedule power
ringing during the next time slot of the ringing portion of the same ringing
cycle. The DMS-100 switch attempts to schedule power ringing during each
time slot of the ringing portion of a ringing cycle until power ringing can be
applied, or the ringing portion of the ringing cycle expires. If power ringing
can not be applied during this ringing cycle, the DMS-100 will try the next
ringing cycle.

Immediate ringing is enabled or disabled by office parameter
IMMEDIATE_RING_ENABLE in table OFCENG.

Note: When changing the office parameter
IMMEDIATE_RING_ENABLEin tableOFCENG toY, considerationmust
be given to the value datafilled for office parameter
ALLOW_RINGING_ON_TIP_SIDE. When this office parameter is set to
Y, a considerable amount of ring slots are reserved for tip side ringing
functionality. This may delay the next available time slot in the ringing
portion of the ring cycle. For more information on office parameter
ALLOW_RINGING_ON_TIP_SIDE,refer to OfficeParametersReference
Manual.

An illustration of normal and immediate ringing for a 1FR (1 flat rate is a
standard line option) is shown in the following figure. This illustration is not
specific to any ringing type. It illustrates the differences in normal and
immediate ringing on a 1FR line when time slot 0 of the ringing cycle is
unavailable.

DMS-100 Family DMS-100 Ringing System BASE15 and up

1-4 DMS-100 ringing overview

Figure 1-2 Normal versus immediate ringing on 1FR line

Ringing request received

Ringing cycle 1 Ringing cycle 2

Normal
ringing
(immediate
ringing
disabled)

Immediate
ringing
enabled

Apply power ringing

01 2 3 4 5 7 86 9 1011 0 1 2 3 4 5 7 86 9 1011

Ringing
applied

12345 786 9 10 11 0 1 2 3 4 5 7 86 9 10110

Time slot 0 not available.
Try cycle 2.

12345 786 9 10 11 0 1 2 3 4 5 7 86 9 10110

6-s delay

Apply power ringing

Time slot 0 not available. Try time slot 1. Time slot 1
available. Apply power ringing at slot 1.

0.5-s delay

Ringing
applied

Time slot 0 available. Apply
power ringing at Time slot 0.

The effects of immediate ringing on the power ringing signal differ between
LME and LCE. In LME, when immediate ringing is enabled, the DMS-100
schedules power ringing during the next available time slot in the ringing
portion of theringing cycle. Ringing is removed at the endof the last time slot
in the ringing portion of the ringing cycle.

For example, in Figure 1-2, "Normal versus immediate ringing on 1FR
line." immediate ringing is enabled on the LME, the first power ringing burst
applies at the start of time slot 1 and continues to the end of time slot 3. This
results in a ringing burst truncated to 1.5 s rather than a complete 2-s burst.

In LCE, like LME, when immediate ringing is enabled, the DMS-100
schedules power ringing during the next available time slot in the ringing
portion of the ringing cycle. Ringing is removed when the 2-s burst has
completed.

297-1001-131 Standard 06.01 October 2000

For example, in the following figure, ringing is enabled on the LCE, the first
ringing burstapplies at thebeginning of time slot1 and continuesto the end of
time slot 4. The initial ringing burst is 2 s.

ANI and coin functions

The DMS-100 ringing bus also providesvoltages for ANI and coin functions.
The ANI and coin voltages include:

• +48 V

• -48 V

• +130 V

• -130 V

Types of ringing

The DMS-100 switch supports the following types of ringing:

• frequency selective ringing

• superimposed ringing

• coded ringing

DMS-100 ringing overview 1-5

• distinctive ringing

• teen ringing

• Japan ringing

Each ringing type is described in the paragraphs that follow.

Frequency selective ringing

Frequency selective ringing is used for service to single party, 2-party, and
multiparty up to eight parties. In the frequency selective scheme, each ringer
on theline is tuned toa specific ringing signalfrequency.When a subscriber is
called, the DMS-100 switch applies to the line the ringing signal where the
called subscriber's ringer is tuned. The called subscriber's ringer, which is
tuned to the applied ringing signal, rings. The remaining ringers on the line,
which are not tuned to the applied ringing signal, reject the ringing signal and
remain silent.

Note: Revertive ringing is not supported for FSR lines.

Revertive calls from FSR lines are permitted. The originator of the revertive
call receivesa treatment, either a tone or an announcement, indicating thecall
is placedto another partyon the same line.The terminating partyalso receives
a treatment. When both parties are off-hook, the talk path is established.

DMS-100 Family DMS-100 Ringing System BASE15 and up

1-6 DMS-100 ringing overview

The treatments for FSR revertive calls are defined in table TMTCNTL,
subtable LNT, in the following tuples:

• originator revertive multiparty frequency with three or more parties
(ORMF)

• originator revertive frequency with two parties (ORAF)

• terminating party (TRRF)

The following figure illustrates the sequence of events that occur when a
revertive call is made on a multiparty, FSR line.

Figure 1-3 Revertive call on multiparty, FSR line

1. Calling party (party 2) goes off-hook, dials called number, receives fast
busy,then hangs up.

Tip
Ring

Dial pulses

Party 1

Party 3

fR=20Hz

(see note 1)

fR=20Hz

Party 2

fR=30 Hz

fR=30 Hz

Party 4

2. The called party (party 4) receives 30 Hz ringing signal.

fR=20Hz

Tip
Ring

30 Hz

Ringing signal

3. When called party answers, the call enters the talking state.

Tip
Ring

Party 1

Party 3

Party 1

Party 3

fR=20Hz

fR=20Hz

(see note 1)

fR=20Hz

Party 2

Party 4

Party 2

Party 4

fR=30 Hz

fR=30 Hz

fR=30 Hz

fR=30 Hz

Note 1: fR indicates the ringer's tuned frequency.
Note 2: The previous diagram does not show the ground connection of the

tip and ring ringing circuits. These grounds are provided at the subscriber's
location.

297-1001-131 Standard 06.01 October 2000

DMS-100 ringing overview 1-7

The frequencies usedinthe frequency selectiveringing scheme are as follows:

• harmonic ringing: 16-2/3 Hz, 25 Hz, 33-1/3 Hz, 50 Hz, 66-2/3 Hz

• synchromonic ringing (20 Hz base): 20 Hz, 30 Hz, 42 Hz, 54 Hz, 66 Hz

• synchromonic ringing (16 Hz base): 16-2/3 Hz, 30 Hz, 42 Hz, 54 Hz

• decimonic ringing: 20 Hz, 30 Hz, 40 Hz, 50 Hz, 60 Hz.

Frequency selective ringing is used by Rural Electrification Association
(REA) offices. The following figures illustrate the REA frequency selective
ringing timing for the following types of ringing:

• synchromonic

• harmonic

• decimonic

Synchromonic ringing

The following figure illustrates the relationship between the synchromonic
ringing signals and the DMS-100 ringing cycle.

Figure 1-4 Synchromonic ringing

6s

02345786101119

FrequencyA
(1 party)

FrequencyB
FrequencyC
FrequencyD

ANI/coin

3300HHzz

11..9955ss

(seenote)

(Any available slot)

02345786101119

4422HHzz

11..3355ss
5544HHzz

11..3355ss
6666HHzz

11..3355ss

Note: Available frequenciesare 16-2/3 Hz,20 Hz, 30Hz, 42 Hz,54 Hz and
66 Hz. Any four of the available six frequencies, in any order, can be
assigned to frequencies A through D: however, 16 Hz and 20 Hz can not be
used simultaneously.

DMS-100 Family DMS-100 Ringing System BASE15 and up

1-8 DMS-100 ringing overview

Harmonic ringing

Thefollowing figureillustrates therelationshipof theharmonic ringingsignals
with the ringing cycle.

Figure 1-5 Harmonic ringing

6s

02345786101119

FrequencyA
(1 party)

FrequencyB
FrequencyC
FrequencyD

ANI/coin

2255HHzz

11..9955ss

(seenote)

(Any available slot)

02345786101119

3333----11//33HHzz

11..3355ss
5500HHzz

11..3355ss
6666----22//33HHzz

11..3355ss

Note: Available frequencies are16-2/3, 25, 33-1/3,50, and 66-2/3 Hz.Any
four of these, in any order, can be assigned to frequencies A through D.

Decimonic ringing

Thefollowing figureillustrates therelationship betweenthe decimonicringing
signals and the ringing cycle.

Figure 1-6 Decimonic ringing

6s

FrequencyA
(1 party)

FrequencyB
FrequencyC
FrequencyD

ANI/coin

297-1001-131 Standard 06.01 October 2000

02345786101119

3300HHzz

11..9955ss

(seenote)

(Any available slot)

02345786101119

4400HHzz

11..3355ss
5500HHzz

11..3355ss
6600HHzz

11..3355ss

Note: Available frequencies are 20 Hz, 30 Hz, 40 Hz, 50 Hz, and 60 Hz.
Any fourofthese, in any order, can be assignedto frequencies A through D.

Superimposed ringing

Superimposed ringing is a form of selective ringing which uses a positive or
negativebiased 20 Hzringing signal andpolarizing devices,such as gas tubes,
at the receiving end for full or semi-ringer selection. In the fully selective
configuration, a maximum of four parties can be connected to one line, with
two on the tip side and two on the ring side.

Theringer connectionsof thefully selectiveringing schemeis illustratedin the
following figure.

Figure 1-7 Fully selective ringer configuration - superimposed ringing

Tip

Ring

DMS-100 ringing overview 1-9

Ringer 2 Ringer 4Ringer 1 Ringer 3

Negative-biasedringersPositive-biasedringers

On both the tip and ring side, the ringer of one party is polarized for a
positive-biased ringing signal, while the ringer of the other party is polarized
for a negative-biased signal.A positive-biased ringingsignal applied to the tip
side, for example, rings only the party on the tip side with the positive-biased
ringer.

In the semi-selective configuration, a maximum of eight parties can be
connected to one line, with four on the tip side and four on the ring side. On
each side, two ringers are polarized for a positive-biased ringing signal, while
the other two are polarized for a negative-biased ringing signal. A
positive-biased ringing signal applied to the tip side, for example, in the
semi-selective configuration, rings only the two parties with ringers polarized
for a positive ringing signal. Becausetwo parties ring simultaneously, a single
ring (code 1) and a 2-ring (code 2) ringing scheme is used to distinguish
between the two parties.

DMS-100 Family DMS-100 Ringing System BASE15 and up

1-10 DMS-100 ringing overview

Revertive calls (calls from a subscriber on a multiparty line to another
subscriber on the same party line) are permitted in the superimposed scheme.
The callingparty receives revertiveringing while thecalled partyis being rung
if the callingparty is on theopposite side, tip or ring,of the called party, or the
calling party is on the same side but with the opposite polarity of the called
party.

If the calling party is on the same side with the same polarity as the called
party, the calling party, after going on-hook, is rung simultaneously with the
called party.

The following figure illustrates a call being placed from the tip side of a
multiparty, superimposed ringing line to a party on the ring side of the same
line with a negatively-biased ringer.

297-1001-131 Standard 06.01 October 2000

DMS-100 ringing overview 1-11

Figure 1-8 Call on multiparty superimposed ringing line

1. Calling party (party 2) goes off-hook and dials called party (party 4).

Tip

Party 1

+R

(see note 1)

Party 2

--R

Ring

Party 3

+R

Party 4

--R

2. The called party (party 4) receives negative-biased ringing signal.

Tip

Party 1

+R

Party 2

--R

Ring

Party 3

+R

Party 4

--R

3. When called party answers, revertive ring on calling party's side ceases,
indicating to the calling party that the called party has answered. Calling
party then goes off-hook and the call enters the talking

state.

+R

Tip

Party 1

Party 2

Ring

+R

Note 1:

Party 3

+R indicates positive-biased ringers and -R indicates negative biased

Party 4

ringers.

Note 2:

This diagram does not show the ground connections of the tip and ring

circuits. These grounds are provided at the subscriber's location.

DMS-100 Family DMS-100 Ringing System BASE15 and up

--R

--R

1-12 DMS-100 ringing overview

The dc component of the superimposed ringing signal determines the ringer
selection.The followingtable liststhe valuesof boththe acand dccomponents
of the superimposed ringing signals.

Table 1-1 Superimposed ringing signal - ac and dc components>

ac dc Frequency (Hz)

86 -38 20
86 +36 20
86 -52 20
86 +52 20
105 +52 20
105 -52 20

The following figuresillustrate the relationshipbetween the ringingsignal and
the DMS-100 ringing cycle.

Figure 1-9 LCE superimposed revertive ringing with no immediate ring

6s

Even LSGs 1, 2

party

Odd LSGs 1, 2

party

3, 4 party

Negativerevertive

splash

Positive revertive

splash

ANI/coin (Any available slot)

01

0.46 s

2345 78610119

2345 7861011901

0.92 s

0.48 s

297-1001-131 Standard 06.01 October 2000

DMS-100 ringing overview 1-13

Figure 1-10 LCE superimposed revertive ringing with immediate ring enabled

6s

0.46 s

0.92 s

0.48 s

01

2345 78610119

Even LSGs

1, 2 party

3, 4 party

Negativerevertive

splash

Positive revertive

splash

(Any available slot)ANI/coin

2345 7861011901

Figure 1-11 LCE superimposed revertive ringing with no immediate ring

6s

0.5 s

--48V1FR,

2FR code 1

+48V 2FR

code 1

--48Vmulti-

party code 2

+48V multi

party code 2

Revertive

splash --48V

Revertive

splash +48V

ANI/coin

02345786101119

02345786101119

DMS-100 Family DMS-100 Ringing System BASE15 and up

1-14 DMS-100 ringing overview

Figure 1-12 LCE superimposed revertive ringing with immediate ring enable

6s

0.5 s

--48V2FR
code 1

+48V 2FR

code 1

--48Vmulti-

party code 2

+48V multi-

party code 2

Revertive

splash --48V

Revertive

splash +48V

ANI/coin

02345786101119

02345786101119

For the LCMof the LCE frame/cabinet with coded immediate ringing andthe
central control (CC) Patch TLA67, power ringing will be applied within 0.5 s
of the start ring back illustrated in the following figure.

297-1001-131 Standard 06.01 October 2000