Nortel DMS-100 Enhanced 911 Numbering Plan Digit Table (E911NPD) |
Table Name
Enhanced 911 (E911) Numbering Plan Digit (NPD) Table
Functional Description of Table E911NPD
Table E911NPD associates a NPD with the Serving Numbering Plan Area (SNPA) of the E911 tandem previously datafilled in table HNPACONT (List of Home NPA Code Subtables).
A SNPA cannot be datafilled against two NPDs. That is, no two tuples in table E911NPD can have the same SNPA.
The NPD is used for single information digit Automatic Number Identification (ANI) format if ANI is forwarded to the Public Safety Answering Point (PSAP).
Note: Table E911NPD is not used if there are no PSAPs served by the E911 tandem that use single information digit ANI format. This format applies when office parameter E911_PSAPS_USING_1_INFO_DIGIT has value "N".
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:
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 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:
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 example 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 from the above example used at each PSAP:
-------------------------------------------------------- NPD Display Information Flashing? -------------------------------------------------------- 0 0 + ANI DN No 1 1 + ANI DN No 2 2 + ANI DN No 3 3 + ANI DN No 0 4 + ANI DN Yes 1 5 + ANI DN Yes 2 6 + ANI DN Yes 3 7 + ANI DN Yes All 8 Maintenance Test Call --------------------------------------------------------
The following conditions apply to the use of the single-digit information digit:
Three-Digit Information Digit
For the three-digit information digit format, the digits are not encoded and no flash signal is provided. Instead, the three digits correlate directly to the calling party 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 + 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.
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 an 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).
Datafill Sequence & Size
Table HNPACONT must be datafilled before table E911NPD. Table size is 0 to 4 tuples.
Datafill
The following table describes datafill for table E911NPD:
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Table E911NPD Field Descriptions
Field Subfield Entry Explanation and Action
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NPD 0 to 3 Numbering Plan Digit
(1 digit) Enter a digit representing single
information digit ANI.
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SNPA 0 to 9 Serving Numbering Plan Area
(1 to digits) Enter the SNPA, already datafilled in
table HNPACONT, of the E911 trunk group
incoming from the end office to the E911
office assigned to that NPD.
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Datafill Example
The following example MAP display shows sample datafill for table E911NPD.
NPD SNPA ____________ 0 919 1 704 |