Nortel DMS-100 Line Module Ring Code Table (LMRNG)

Table Name

Line Module Ring Code Table

Functional Description of Table LMRNG

Table LMRNG specifies the type of ringing assigned to each Line Module (LM) or Remote Line Module (RLM).  The following types of ringing are supported:

The type of ringing for Line Concentrating Modules (LCM), Remote Line Concentrating Modules (RLCM), International Line Concentrating Modules (ILCM), International Remote Line Concentrating Modules (IRLCM), ISDN Line Concentrating Modules (LCMI), and Enhanced Line Concentrating Modules (ELCM) is specified in table LCMINV.

Regular type audible ring is returned to the calling party for all types of ringing.  On revertive calls, ring splash is applied to the originating line (with the exception of Coded Ringing Based on Cyclic Variation of 30 Hz and Frequency Selective Ringing).

A Line Module Equipment (LME) frame and a RLM frame have two ringing generators and two LCMs.  Under normal operating conditions, one ringing generator serves one LCM.  If one of the ringing generators on a frame fails, the remaining ringing generator serves both LCMs on the frame.

The maximum number of lines that can be assigned to a LM bay is 640, or 1,280 for each LME frame.  The switching unit can have a mixture of frequency, coded, and superimposed ringing.  Only one type of ringing can be assigned for each LME frame (1,280 lines).

Coin Presence Voltage

The standard coin presence test uses a -52 VDC source from the ringing generator applied to the tip side of the coin line.  If more than 10 mA of current flows during this voltage application (250 ms), the presence of the initial rate in the coin slot is indicated.

To accommodate local coin overtime, a partial coin presence test using +52 VDC from the ringing generator is used.  If more than 10 mA flows, the presence of a coin or coins (any denomination) in the coin slot is indicated.

If the coin presence test voltage (field CNPRESV) in table LMRNG is set to "25V", then -25 VDC is used to test for initial deposit and +25 VDC is used to test for partial coin presence.

On short loops, -52 VDC coin presence can cause activation of the coin return and collect relay due to low internal resistance of the coin return and collect circuit on the coin phone.  Coin phones on loops having a loop resistance of less than 200 ohms can experience this.  Some examples of coin relay operating currents are shown in the following table:


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Examples of Coin Relay Operating Currents

Coin Unit                  Operate Current     Non-Operate Current
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Western Electric 1C/2C     41 mA               30 mA 
Automatic Electric 120B    48 mA               39 mA
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Coin dialtone-first phones on short loops must be wired to a LM datafilled in table LMRNG with a -25 VDC coin presence voltage.  Coin-first phones do not undergo a coin presence test for the initial rate; but, if local coin overtime is active, a coin presence test is used for the overtime rate and coin-first phones on short loops must be wired to a LM datafilled in table LMRNG with a +25 VDC coin presence voltage.

The coin presence test fails if the coin presence test current is less than 10 mA.  Coin phones on long loops from a LM using -25 VDC coin presence can experience failures due to loop resistance.  The maximum allowable loop resistance for a coin phone using -25 VDC coin presence tests is 1,200 ohms.  If a LM does not have any short-loop coin phones wired to it, the LM must use -52 VDC coin presence.

Coded Ringing Based on Cyclic Variation of 20 Hz

Coded 20 Hz ringing is provided for multiparty lines if the ringers of all parties on the tip side or all parties on the ring side are rung simultaneously.  Each of the parties on the tip or ring side has a different ringing code, to differentiate between parties.

Single-party and two-party lines are assigned ringing code "0" in table LENLINES.  The ringing cycle is two seconds on and four seconds off.  The six-second ringing cadence for each of the five available ringing codes is shown below in the following table:

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Ringing Cadences for Coded 20Hz Ringing

Ringing Code Input
for table LENLINES     Ringing Code     On    Off   On    Off   On    Off (seconds)
----------------------------------------------------------------------------------------------
0                      Code 0           2.0   4.0
1                      Code 1           1.5   4.5 
2                      Code 2           1.5   0.5   1.5   2.5
3                      Code 3           1.5   0.5   0.5   3.5
4                      Code 4           1.5   0.5   0.5   0.5   0.5   2.5 
5                      Code 5           1.5   0.5   0.5   0.5   1.0   2.0
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The maximum number of lines on a LM bay (640 lines) that can ring simultaneously is 15 for each ringing generator.

Coded Ringing Based on Cyclic Variation of 30 Hz

Coded 30 Hz ringing provides distinctive ringing patterns at 30 Hz to differentiate the type of call, ringing patterns for ring again and call back queueing, ring splash for call forwarding, and emergency service bureau ring back.

Coded 30 Hz ringing does not support two-, four-, eight-, or ten-party lines, or revertive splash ringing.  The six-second ringing cadence for coded 30 Hz ringing is identical to the ringing cadence for coded 20 Hz ringing.

Coded Special Ringing Based on Cyclic Variation of 20 Hz

Coded 20 Hz special ringing provides four short (0.5 seconds) bursts for Ring Code 5, as shown below in the following table.

Ring Codes 0 to 4 and their cycles are identical to the ring codes for coded 20 Hz ringing shown in the following table

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Ringing Candence for Coded 20 Hz Special Ring Code 5

Ringing Code    On    Off   On    Off   On    Off   On    Off (seconds)
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Code 5          0.5   0.5   0.5   0.5   0.5   0.5   0.5   2.5 
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Superimposed Ringing

Superimposed ringing is used for semiselective ringing on eight-party lines and fully selective ringing on four-party lines.  With superimposed ringing, the 90 VAC, 20 Hz ringing current is biased with 40 or 48 VDC (as specified in field PROMVOLT of table LMRNG) and is dependent on the type of PROM used in the ringing generator.

Single-party and two-party ring-side lines are assigned "Ringing Code 1-".  Two-party, tip-side lines are assigned "Ringing Code 1+".  The six-second ringing cadence for each of the four available ringing codes is shown below in the following table:

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Ringing Cadences for Superimposed Ringing

Ring Code Input
for Table LENLINES    Ringing Code       On    Off   On    Off (seconds)
----------------------------------------------------------------------------------------------
1                     1-                 2.0   4.0
2                     1+                 2.0   4.0 
3                     2-                 1.0   0.5   0.5   4.0 
4                     2+                 1.0   0.5   0.5   4.0
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The maximum number of lines on a LM bay (640 lines) that can ring simultaneously is 15 for each ringing generator.

Frequency Ringing

Frequency ringing uses a different frequency and a specially tuned ringer for each party.

Four types of frequency ringing are available: decimonic, harmonic, synchronic 16, and synchronic 20.  Each LM can be assigned four of the five available frequencies.  The four frequencies selected are datafilled in table LMRNG.

The primary frequency for a LM is the frequency in table LMRNG assigned as "frequency A," not necessarily the lowest frequency.

Multiparty lines are assigned as frequencies A, B, C, and D.  Single-party lines assigned to Ring Code 0 in table LENLINES receive the primary frequency (frequency A).

The following table shows the five frequencies available for each of the types of frequency ringing, the ringing code used to access each, and the maximum number of lines on a LM bay (640 lines) that can ring simultaneously for each ringing generator.

If the frequency is a partial number (for example, 16.67 Hz), for input purposes the frequency is rounded off to the next highest number.  The numbers used as input for these frequencies are enclosed in brackets and are shown after the actual frequency in the following table.

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Frequencies Available for Frequency Ringing Types

Ring Code Input      |----Decimonic----|   |-----Harmonic----|   |---Synchronic--------------|
for Table LENLINES   Frequencies   Lines   Frequencies   Lines   Frequencies (16)  (20)  Lines
----------------------------------------------------------------------------------------------
0                    Primary               Primary               Primary            Primary
1                    20            12      16.67 (17)    15      16                 20   12
2                    30            9       25            11      30                 30   9 
3                    40            6       33.33 (34)    7       42                 42   6 
4                    50            4       50            4       54                 54   4 
5                    60            4       66.67 (67)    3       66                 66   3
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Each LM can be assigned only four frequencies.  If the ringing code of the fifth frequency is specified, the ringing code for the line defaults to the primary frequency.

If the ringing code in table LENLINES is 0 (zero), the station is assigned the primary frequency and a six-second ringing cycle of 1.95 seconds ringing on and 4.05 secconds ringing off.

If the ringing code in table LENLINES is 1 to 5, the station is assigned the six-second ringing cycles for frequencies A, B, C, and D as shown in the following table:

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Ringing Cycles for Frequencies A, B, C, and D

Frequency     Off    On     Off (seconds)
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A (primary)   0.60   1.35   4.05 
B             1.95   1.35   2.70 
C             3.30   1.35   1.35 
D             4.65   1.35   1.35
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The hardware Product Engineering Codes (PEC) that support the various ringing types are shown below in the following table:

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Ringing Generator Interface Types and PECs

Hardware PEC         Ringing Types Supported
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2X27AA               Coded 20 Hz and Superimposed
2X27AB               Decimonic and Coded 30 Hz 
2X27AC               Harmonic 
2X27AD               Synchronic 16 
2X27AE               Synchronic 20
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Datafill Sequence & Table Size

Table LMINV must be datafilled before table LMRNG. Size is 0 to 512 tuples.

Datafill

The following table describes datafill for table LMRNG:

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Table LMRNG Field Descriptions

Field       Subfield       Entry               Explanation and Action
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FRAMENO                    See Subfields       Frame Number
                                               This field consists of subfields SITE and FRAME.
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            SITE           Alphanumeric        Site
	                   (1 to 4 characters  If office parameter USINGSITE in table OFCOPT and 
			   or blank)           office parameter UNIQUE_BY_SITE_NUMBERING in 
			                       table OFCENG are both equal to "Y" (yes), and if
					       the line is remote from the host, enter the site
					       name assigned to the remote location.  Otherwise,
					       if the line is located at the host, leave the 
					       subfield blank and SITE is datafilled by default
					       with HOST.  If parameter USINGSITE in table 
					       OFCOPT is equal to "Y" and parameter 
					       UNIQUE_BY_SITE_NUMBERING in table OFCENG is equal
					       to "N" (no) (numbering is unique by office), the
					       entry in subfield SITE is optional.  If SITE is 
					       entered, it is checked for a match in one of the 
					       tables to which lines are assigned.  If SITE is 
					       not entered, it is not datafilled by default and 
					       is not checked against one of the tables to which 
					       lines are assigned.  The first character of all 
					       entries for this subfield must be alphabetic. 
					       If office parameter USINGSITE in table OFCOPT is
					       equal to "N", leave this subfield blank.

            FRAME          0 to 511            Line Module Frame Number
	                                       Enter the LM or RLM frame number.
					       Frame numbers for NT40 range from 0 to 127.
					       Frame numbers for SuperNode range from 0 to 511.
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CNPRESV                   52V or 25V           Coin Presence Voltage
                                               Enter the voltage to use for coin presence tests.
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RNGDATA                   See Subfields        Ring Data
                                               This field consists of subfield RNGTYPE and
					       refinements FREQUENCIES and PROMVOLT.

            RNGTYPE       C, CSR, C30, F, S,   Ring type Enter one of the following types of
	                  or UNASSIGNED        ringing to assign to the line module:

                                               "C" for coded ringing based on cyclic variation
					       of 20 Hz.

					       "CSR" for coded 20 Hz special ringing.

					       "C30" for coded ringing based on cyclic variation
					       of 30 Hz.

					       "F" for frequency ringing and datafill refinement
					       FREQUENCIES

					       "S" for superimposed ringing and datafill 
					       refinement PROMVOLT

					       "UNASSIGNED" if changing the ring type of a tuple.
					       
                                               Note: Values C5A, C5B, C3C, or C3D can appear in
					             the range of entries for field RNGTYPE; 
						     these are not valid entries for table 
						     LMRNG and are rejected if entered.

            FREQUENCIES    See Subfields       Frequencies
	                                       If the entry in subfield RNGTYPE is "F", 
					       datafill this refinement.  This refinement
					       consists of subfields A, B, C, and D.


            A              16, 17, 20, 25,     Frequency A
	                   30, 34, 40, 42,     Enter the frequency assigned as frequency A
			   50, 54, 60, 66,     (primary frequency).
			   67, or blank

            B              16, 17, 20, 25,     Frequency B
	                   30, 34, 40, 42,     Enter the frequency assigned as frequency B.
			   50, 54, 60, 66, 
			   67, or blank 

            C              16, 17, 20, 25,     Frequency C 
	                   30, 34, 40, 42,     Enter the frequency assigned as frequency C.    
			   50, 54, 60, 66, 
			   67, or blank 

            D              16, 17, 20, 25,     Frequency D 
	                   30, 34, 40, 42,     Enter the frequency assigned as frequency D.
			   50, 54, 60, 66, 
			   67, or blank

            PROMVOLT       40V or 48V          PROM Offset Voltage
	                                       If the entry in subfield RNGTYPE is "S", datafill
					       this refinement.  Enter the PROM offset voltage 
					       required for the PROM in the ringing generator.
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EXPRETRP                   Y or N              Extend Pretrip 
                                               If DMS-1 links are present in the LM, enter "Y" 
					       (yes) to extend the ringing pretrip to 200 ms. 
					       Otherwise, enter "N" (no).
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-End-

Datafill Example

Sample datafill for table LMRNG appears in the following example:


FRAMENO    CNPRESV    RNGDATA    EXPRETRP
____________________________________________________________
HOST 0     52V        C          N