Nortel DMS-100 Enhanced 911 Emergency Service Number Table (E911ESN)

Table Name

Enhanced 911 Emergency Service Number

Functional Description of Table E911ESN

All E911 tables (except E911SRDB - which is optional) are required for Enhanced 911 (E911) Emergency Service.

E911 trunks can be dedicated for incoming 911 calls (datafilled in table TRKGRP with trunk group type E911).  E911 type trunks support both Multi-Frequency (MF) and Dial-Pulse (DP) signaling formats in accordance with the following conditions:

Any outgoing (wink-start) trunk from the end-office that is capable of spilling ANI and conforms to Feature Group C signaling can interface with an incoming E911 trunk at the E911 tandem.

Table E911ESN associates an Emergency Service Number (ESN) with a flash-control field, a primary Public Safety Answering Point (PSAP) name, and up to six secondary PSAP names.  Secondary PSAPs are used in call transfers made by a primary PSAP attendant.

This table stores all the PSAPs (maximum of seven) for each of the ESNs.  The information for each ESN also contains a flash field.

The order of the secondary PSAPs at all E911 offices need not be the same.  However, within each office, all the PSAPs in a table column must correspond to the same type of agency (for example, fire department).  It is the responsibility of the operating company to confer with the PSAP agencies and reach a common agreement as to the location of the types of agencies in this table.  Values of fields PRIMPSAP, and PSAP1 to PSAP6 are names of PSAPs already datafilled in table E911PSAP and are intended to indicate the type of service provided, for example, RALEIGHFIRE.  All secondary PSAPs providing a particular service, for example a fire department, must be datafilled as the same field, PSAP1.  If a particular emergency service zone does not offer a particular emergency service, that field must be datafilled as "NONE."  Selective transfer codes *11 through *16 dialed by the PSAP operator correspond to PSAP1 through PSAP6.

A PSAP name can be datafilled in this table only if it already exists in table E911PSAP.  Of the seven PSAPs, PRIMPSAP is always the primary PSAP.  For example, police might be the primary PSAP and the other six are secondary PSAPs (fire, ambulance, poison control, rescue, and so on).

If, for any reason, a particular emergency service other than the primary PSAP is not being provided by the Emergency Service Zone (ESZ), then the value "NONE" must be entered as the PSAP name for that field.  The value "NONE" can be entered as a default PSAP name for any secondary PSAP, but not for a primary PSAP.

Regenerated ANI Format

The E911 feature requires ANI information from an end-office.  The E911 tandem uses ANI information to facilitate selective routing which is regenerated to the PSAP.  The sequence for transmitting ANI information is as follows:

  1. The end-office transmits ANI information to the E911 tandem.
  2. The E911 tandem regenerates ANI data and outpulses the data, along with information digits to the PSAP.  The E911 tandem transmits the data by standard multifrequency pulses.

ANI information is outpulsed to the PSAP in the form of Key Pulse (KP) + Information Digit + NXX-XXXX + Start (ST), where NXX-XXXX is the ANI Directory Number (DN) of the calling station.

E911 offers single-digit and three-digit information digit formats for transmitting ANI data, as well as substitute ANI codes that can be used in the event of ANI failure or in cases where an end-office is not equipped for ANI operation.  The choice of ANI format is left to the operating company and is determined on a per-office basis.

Single-Digit Information Digit

In the single-digit information digit format, the single digit is encoded so that it represents both the calling party's Numbering Plan Digit (NPD) and a flash-control signal.  The E911 tandem outpulses the ANI information to the PSAP in the form of standard MF pulses.  These pulses are sent in the following order:

  1. Key Pulse (KP) digit.
  2. Encoded single-digit information digit representing the calling party's NPD and a flash-control signal.
  3. ANI DN.  Normally the billing DN of the originating station.
  4. Start (ST) signal.

A single information digit is encoded according to a combination of the following values:

The value of the flash-control field combined with the value of the NPD constitute the encoded information digit.  For example, an E911 tandem serves four NPAs, the PSAPs are equipped with flashing ANI display units, and the telephone operating company has assigned one PSAP as the primary PSAP for all Foreign Exchange (FX) lines terminated outside the E911 service area.  FX lines are used in this example because additional call handling by the PSAP attendant may be required.

If the flash-control field for the FX caller's ESN is datafilled as "ON" (1), the information digit shown in the ANI format causes a flashing display of the calling party's DN, complete with an encoded digit representing the caller's NPA.

The following table gives the determination of the single-digit information digit.

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Single-Digit Information Digit Determination

NPA    NPD    Flash-Control    Information Digit
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919    0      0                0 
518    1      0                1 
201    2      0                2
312    3      0                3 
919    0      1                4 
518    1      1                5 
201    2      1                6 
312    3      1                7 
                               8 (test call) 
			       9 (not used)
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The information digit is used at the PSAP in the following manner:

The following conditions apply to the use of the single-digit information digit:

Information Digit Format (NPA)

Feature AN0930 enhances the E911 tandem by allowing the support of up to 16 NPAs.

For the NPA, the three digits are not encoded and no flash signal is provided.  Instead, the three digits correlate directly to the calling party's NPA.

The format for sending ANI data is the same for three-digit and one-digit information digits: ANI information outpulsed to the PSAP in the form KP + Information Digit (NPA) + NXX-XXXX + ST, where NXX-XXXX is the ANI DN of the calling station.  With the three-digit format, however, the information digits are normally the calling station's NPA.  Because the three digits bear a one-to-one correlation to the calling party's NPA, no encoding is required and no flash is provided.  The pulses are sent in the following order:

  1. Key Pulse (KP) digit.
  2. Information digit representing the calling party's NPA.
  3. ANI DN.  Normally the billing DN of the originating station.
  4. Start (ST) signal.

Substitute ANI Formats

An end-office can still be part of the E911 system, even if it is not equipped for ANI operation or cannot outpulse the digits 911.  In this case, an emergency call is recognized by being routed over a dedicated E911 trunk group.

If a 911 call without ANI information is received or if ANI failure has occurred, the E911 tandem generates a substitute ANI DN code.  This substitute code can take one of the following two forms:

When incoming calls to the E911 tandem are in either the Bellcore standard ANI format or the North Electric AMR 4/5 format, the tandem deletes the existing information digits and replaces them with an encoded information digit NPD.

Selective Transfer

Selective transfer is initiated when the PSAP operator uses the speed-calling code format *11 to *16 to designate call transfer to PSAP1 through PSAP6 from table E911ESN.  Similar emergency services should be datafilled vertacally in table E911ESN.  Every ESN designated PSAP1 would, for example, be for a fire DN datafilled in table E911PSAP.

Speed-calling code *10 designates a selective transfer to the primary PSAP when dialed from any secondary PSAP.  Speed-call code *10 can also be used to transfer the call from a member of the primary PSAP to other members of the primary PSAP or overflow routing for the primary PSAP.

Datafill Sequence

Table E911PSAP must be datafilled before table E911ESN.  The size of this table is 1,000 entries since an E911 office serves a maximum of 1,000 ESZs.

Datafill

The following table describes datafill for table E911ESN:

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Table E911ESN Field Descriptions

Field       Subfield       Entry                     Explanation and Action
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ESN                        0 to 15,999               Emergency Service Number
                                                     Enter a number up to five digits 
						     representing an Emergency Service Zone
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FLASH                      Y or N                    Flash 
                                                     Enter "Y" (yes) to alert the Public Safety
						     Answering Point (PSAP) attendant that the
						     calling party using this Emergency Service
						     Number (ESN) needs special attention or the
						     call is incoming on a message or FX trunk.
						     Otherwise, enter "N" (no).
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PRIMPSAP                   Alphanumeric              Primary Public Safety Answering Point
                           (1 to 16 characters)      Enter a PSAP name already datafilled in 
			                             table E911PSAP and intended to indicate the
						     type of service provided. 
						     "NONE" is not a valid entry.
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PSAP1                      Alphanumeric              Secondary Public Safety Answering Point 1
                           (1 to 16 characters)      Enter a PSAP name already datafilled in 
			                             table E911PSAP and intended to indicate the
						     type of service provided.
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PSAP2                      Alphanumeric              Secondary Public Safety Answering Point 2
                           (1 to 16 characters)      Enter a PSAP name already datafilled in 
			                             table E911PSAP and intended to indicate the 
						     type of service provided.
(to PSAP6)
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Note:  All secondary PSAPs providing a particular service must be datafilled as the same field,
for example, fire as PSAP1.  If a particular emergency service zone does not offer a particular
emergency service, that field must be datafilled as NONE.
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-End-

Datafill Example

The following example MAP display shows sample datafill for table E911ESN.


ESN     FLASH     PRIMPSAP    PSAP1     PSAP2          PSAP3  PSAP4  PSAP5  PSAP6
_________________________________________________________________________________
123     N         CARYPOLICE  CARYFIRE  CARYAMBULANCE  NONE   NONE   NONE   NONE