Number Portability and the Wireless Carriers

NENA Technical Development Conference held in Orlando, FL March 1-4, 1998

The following three articles about the TDC are organized by CPE track, Data Base track, and Network track:



Submitted by Randy Richmond, Zetron, Member of NENA PSAP Standards Committee



The following issues were discussed regarding their impact on PSAPs and CPE.

Wireless Issues:

  • Who should be responsible for Emergency Services Routing Digit (ESRD/pANI) assignment for Phase I? PSAP, state, LEC or NENA? Not resolved.
  • What new network connections will be required for Phase II data?
  • ALI displays. Will map capability be required for Phase II?
  • Can embedded base support Phase I/II? Consensus was that it must.
  • Location Determining Equipment (LDE) technology used should have no impact on PSAP users. May require different interfaces to match LDE.

Year 2000 Issues:

  • Concern exists especially on PCs with older BIOS and those using Win 3.1.
  • Suggests testing to Bellcore GR-2945 to ensure compliance.

Local Number Portability (LNP) Issues:

  • How to access multiple databases?
  • Effect on call-setup time for inbound calls and call backs?
  • What will happen to ANI of abandoned calls?

Integrated Work Station (IWS) Study Group Goals:

  • Develop industry definitions/acronyms
  • Integrate recommendations into NENA-04-001
  • Define various levels of integration between phones, radio, CAD, etc.
  • Standards & Integration documents should be up for review April 2.


The NENA Generic Standards for E 9-1-1 PSAP Equipment, NENA-04-001, has been released since June 1996. It is a good resource for PSAP managers, especially those considering the purchase of new equipment. It defines recommended interfaces, features, reliability and quality of equipment related to 9-1-1 call taking. Many PSAPs are now referencing this in their bid specs. Of particular interest to those concerned about Dept of Justice ADA reviews is that the DOJ often uses NENA-04-001 to review compliance. Copies are available for download from the NENA web-site (


The PSAP Standards Committee plans to release a revised edition of NENA-04-001 in time for the National NENA Convention in June. The second edition will cover ACDs (including the use of TDDs in an ACD environment), 10/20 digit ANI (used for Phase I), and recorder beep recommendations. The Committee is also working on an edition for ISDN-based 9-1-1 equipment.


Data Base Track

Submitted by Marlys Davis, King County 9-1-1, 206-296-3911


The two highlights of the Technical Development Conference were Wireless 911 and Local Number Portability. Both of these issues as they relate to 911 data bases were addressed in the Data Base Track.




Wireless 911


NENA has recommended standard formats for data exchange. The current NENA recommended format for data exchange is NENA Version 2. Most of your E911 data bases are probably formatted under this standard. In response to wireless 911, the NENA Data Standards Subcommittee has drafted an update for Version 2 and drafted a new Version 3.


The revised Version 2 includes data fields for the display of latitude, longitude, altitude, and cell site and sector ID. Version 3 recommends a new philosophy in which the data fields have varying lengths, with a specified maximum length, but no standard placement within the data stream. These are known as “tag” data records, in which data fields are identified by their pre-defined tag labels, not by their placement within the data stream. This will allow for faster programming changes, more efficient data transmission, and smaller file sizes. Version 3 also includes the additional fields which are necessary for wireless 911 service. The NENA Data Standards Subcommittee has recommended that all Service Providers implement NENA Version 3 by January 1, 2000.


At the Subcommittee meeting on wireless 911, there was much discussion about standards for the display of wireless Phase I information on the ALI display. The Subcommittee decided that since they only recommend standards for data exchange, and have not established standards on how this information is to display at the PSAPs, they would not establish a standard for the display of Phase I information. Since different areas of the country have already been working to determine how this data should display at their PSAPs, the Subcommittee did decide to compile these different formats for distribution as samples which can be used by others throughout the country.


There was also discussion about adding fields for the textual display of Phase II location information on the ALI screens. Due to the fact that not all PSAPs may be in a position to install mapping, and as a back-up to the mapping system, it was suggested that the location information should also display on the traditional ALI screens. At this time, there is no data field available in the revised Version 2 or Version 3 for this information.


Also in response to wireless 911, a new term was developed and presented at the Conference. The term Pseudo-ANI, or pANI, has traditionally been used within the 911 industry for a variety of purposes, largely associated with the interface of PBXs to E911 systems. In also using the term pANI to designate a fictitious number which identifies wireless cell sectors, there was too much confusion regarding the use of this term. As a result, a new term “Emergency Service Routing Digits” (ESRD) has been created to designate wireless cell sector ID.


Local Number Portability


In response to Local Number Portability (LPN), in which a subscriber can keep their same phone number while changing service providers and moving within their local rate center, the NENA Data Standards Subcommittee has established a new data field for Telephone Company Identification. This data field is included in the revised Version 2 and Version 3. All telephone service providers are encouraged to register with NENA for a Company ID. NENA has made the list of telephone companies, with their IDs and other pertinent information, available on their web site at A current copy of this list is provided, with a designation for which companies provide service within Washington State.


Each county must decide whether to update their data base to include the Company ID field. PSAPs are advised to check with their CAD vendor to determine what impact this data stream addition will have on their CAD when transferring information from the ALI screen into CAD. This new field appears towards the end of the ALI data stream, and in most cases, it should have no impact on the CAD system.


Network Track

Submitted by Rod Proctor, Proctor & Associates, 425-881-7000


The main thrust of the Network Track was the impact of the FCC 94-102 order regarding ANI information and location data for wireless callers. Phase One approaches were discussed and various architectures such as, Call Path Associated Signaling and Non-Call Path Signaling were described and discussed. The concept of using ESRDs (Emergency Service Routing Digits) was introduced to replace the pANIs currently used for network routing. This was done to avoid confusion between the two numbering plans and who controls them.


There were discussions about the latency of CAMA/FGD connections vs. the speed of SS7. This was countered by ease of using CAMA/FGD and some peoples concerns about the reliability of SS7. There are many problems to be solved before the E9-1-1 network can be totally embedded into the SS7 signaling scheme. The current reliability of the E9-1-1 network is due to the fact it is a somewhat separate and diverse subset of the normal network.


It seems that Phase One is possible now using two or three different methods. The biggest factor is a funding mechanism being in place to pay for the service. Phase Two is not well defined with respect to the location determining equipment (LDE) and the position determining equipment (PDE). The location determining equipment ranges from RF methods to Global Positioning (GPS) solutions. The position determining equipment must process X,Y and maybe Z information into points on a map and standard street addresses. This equipment may also determine the routing of a call in real-time. There will be new data elements such as, Coordinate Location, Confidence Factor, Speed & Direction, etc. All of this will impact the network and CPE both from a voice and data perspective. Location Information Displays will be much more complex and most likely graphic.


The bottom line is that there are many paths to being able to locate cellular handset users and that the 9-1-1 community will not all take the same path so, we will see most of the solutions being implemented somewhere. Most will wait for demonstrations of the various technologies before committing to buying new equipment and services. One lingering question remains from the Conference. Is the 125 meter accuracy, 67% of the time, good enough to make critical dispatching decisions?



Submitted by Allen Jakobitz, State 9-1-1 Office, 360-923-4515


What does every telecommunicator have at arm?s reach? A map. Electronic mapping is an eventuality in every PSAP. The Washington State E911 Office contracted with the Spokane County Geographical Information Systems Division to produce a simple, cost-effective electronic map interface. The prototype will be demonstrated after the May 7th NENA meeting in Goldendale. The expected result is a product that will be free to all users (There will be a $100 per installation MapObjects licensing fee.) This product will utilize local or generic maps in conjunction with the ALI data to allow telecommunicators to visualize locations. Occasionally, a call may come in from a place that is unknown to the telecommunicator. CallMapper will be a tutorial tool to give the telecommunicator a better geographic reference to learn new locations. Most importantly, when a caller doesn?t know where they are (cellular) or is reporting another location (distant fire) CallMapper will provide the tool for fast, accurate spatial information.Below you will find a copy of an actual CallMapper screen. Note that the actual location of the ALI address is pinpointed on the map; 1026 Broadway. Below the map are the most current 9-1-1 calls and their associated ALI. The history file can hold up to 500 ALI data streams. So as to not be distractive to the user, this display is not automatic. All ALI data streams are recorded as they come in. The telecommunicator chooses when to display by double clicking on the ALI record to be shown on the map. This product should be ready for its first full release after some beta testing at Spokane. If CallMapper is found to be of interest to other PSAPs, a simple installation will get the new user up and running. Small modifications may be necessary dependent up the actual ALI data stream. As always the map data?s accuracy can only be controlled by the using agency. CallMapper is a natural segue between paper maps and the 2001 receipt of actual x,y location. Thanks to the hard work of Mike Stewart and Ian Von Essen of Spokane?s GIS, every PSAP in the state will have the opportunity to have a low cost, electronic map solution.





The Washington NENA Technology Subcommittee will have a teleconference on

July 28th (Tuesday) at 10:30am. Call in number is 206-205-0999.