Public Safety-Wireless Industry Consensus
Wireless Compatibility issues, CC Docket 94-102

At the invitation of the Cellular Telecommunications IndustryAssociation (CTIA), representatives of three public safetycommunications organizations met with CTIA officials duringNovember and December 1995 to examine possible areas of agreementon the wireless compatibility issues in CC Docket 94-102. Thepublic safety organizations,

National Emergency Number Association (NENA),

Association of Public-Safety Communications Officials (APCO), and

National Association of State Nine One One Administrators(NASNA),

have participated jointly in the docket through comments andreply comments. The following consensus statement covers issueson which substantial agreement was reached. Where minordifferences remain, these are identified.

The use of the terms “Wireless Industry” and”Public Safety Communicators” (PSCs) reflects theoptimism of the four organizations — CTIA, NENA, APCO and NASNA– that their consensus constitutes a viable basis for commitmentby other industry and public safety associations.

Automatic number identification (ANI)
and automatic location identification (ALI)

1. The Wireless Industry will move immediately to “PhaseI” E9-1-1, the provision of cell site information using a 7or 10- digit pseudo-ANI and a 7 or 10-digit caller ANI (i.e.calling party number), depending on the local landline network’ssignaling capability.

2. The Wireless Industry and the Public Safety Communicators willabandon the FCC’s proposed “Phase II” (3-year) radiolocation objective as not meeting the needs of the industry for abridge to “Phase III” capability or of the 9-1-1community for reliable location information.

3. The Wireless Industry will achieve, during new Phase II — nolonger than 5 years from the FCC’s adoption of rules — theability to locate, in latitude and longitude, a wireless callerwithin 125 meters Root Mean Square (RMS).

Comment. The use of a “Probability” of location withina stated area is a reflection of the Wireless Industry’s concernthat no terrestrial ALI technique now envisioned will be able toperform to the 125-meter tolerance 100% of the time. The”bell curve” distribution of differences between trueand estimated position is illustrated by Exhibit 2, reflectingactual results measured by Associated Group, a vendor-participantin Docket 94-102, for trials conducted in Rochester, Philadelphiaand Baltimore. The “tail” of the curve at the rightedge of the graph demonstrates that some relatively small numberof estimates will be off by more than 500 feet (152.4 meters).

In the Associated Group trials, the RMS distance turned out to be375 feet, or 114 meters. According to a company spokesmanfamiliar with the tests, this level of accuracy was achieved70-75% of the time. If the curve plotted from the results were”normal” (Gaussion), statistical theory holds that RMSdistance would represent 63 to 68% probability of containmentwithin an area around true position — depending on whether thearea were more nearly circular or elliptical. Thus, roughlyspeaking, to prescribe “125 meters RMS” is to requirethat degree of ALI accuracy from two-thirds to three-fourths ofthe time.

4. The PSCs acknowledge the additional concern of the WirelessIndustry that in exceptional cases — which may represent entireserving areas or “pockets” within serving areas — the125-meter RMS standard may be difficult or impossible to meet.The parties have agreed to work on this in good faith as an”implementation issue” which need not delay theadoption of the general rule.

Financial and legal liability

1. In moving to Phase II, a cost recovery mechanism is needed tofund both carrier (wireless and wireline) and PSAP investment inE9-1-1 technology and 9-1-1 cost of service. This could be in theform of public appropriations or bond issues, with or without aseparate 9-1-1 subscriber line fee (e.g. 75 cents a month), whichcarriers would be compensated at customary rates to collect.

Comment. The parties agree, and would ask the FCC to declare,that state or local 9-1-1 fees or taxes reasonably related torecovery of prudently-incurred wireless system or service costsare not barred as a matter of law. They also agree, and would askthe FCC to state, that such fees or taxes should not discriminatebetween wireline and wireless carriers involved in delivery of9-1-1 services. The parties agree to work in good faith towardthe adoption of state and local legislation fairly designed forcost recovery under these principles.

2. The FCC should address and resolve carrier and PSAP legalliability issues.

Comment. The Parties believe that the wireline experience, inwhich callers generally have been held to consent implicitly tothe disclosure of calling number, location and associatedinformation, is applicable to wireless 9-1-1 communications.Similarly, PSAP and wireline experience with state “GoodSamaritan” statutes is applicable to wireless 9-1-1communications.

3. Specifically, the FCC should address and resolve whether theconstraints on disclosure of information to law enforcementofficials in Section 103(a)(2)(B) of P.L. 103-414, theCommunications Assistance for Law Enforcement Act of 1994, affect9-1-1 operations and legal liability.

Comment. The parties believe that, despite the 1994 act’s expresslanguage barring caller location disclosure (except where”determined from the telephone number”), Congress didnot intend to preclude location determination and disclosure viaother means (such as ALI), in the ordinary course of good-faith9-1-1 operations.

Selected additional issues

Access by speech/hearing-impaired callers (NPRM paragraph 54).The FCC proposed a Phase I requirement that 9-1-1 access beavailable to speech- and hearing-impaired individuals throughmeans other than voice-only mobile radio handsets, such as texttelephone (TTY) devices. The parties agree.

Re-ring/callback (paragraph 52). The FCC proposed to require, atPhase II (3 years from order), that “wireless systems mustprovide PSAP attendants with the capability to call back the9-1-1 caller if the call is disconnected,” so long as”the mobile user has not turned off the mobile unit.”The parties agree to an earlier adoption.

Comment. The parties acknowledged that the Wireless Industry’sagreement to provide ANI and pseudo-ANI in Phase I (see above)will make it possible for the PSAP to dial back a 9-1-1 callerunder the indicated circumstances. They also agreed that the”automatic re-ring” features of the wireline networkneed not be required at this point.

9-1-1 availability (paragraph 41). The FCC proposed as a Phase Irequirement that a caller “have the ability to reachemergency services from any service initialized mobile radiohandset in a home service area or a subscribed-to roamed servicearea by dialing only 9-1-1.” The NPRM explained that serviceinitialization means a “user has purchased services from awireless service provider,” and that 9-1-1 is to beavailable “without a requirement for user validation.”The parties agree.

Equipment labeling (paragraph 55). The FCC was less firm with itsproposals in this area, partly owing to uncertainty about theextent to which wireless compatibility would be a function ofsubscriber equipment versus network infrastructure and features.It suggested a warning that might be placed on both phones andoutside packaging, simply stating that location and callbacknumber might not be automatically known to the PSAP taking the9-1-1 call.

Comment. Acknowledging that wireless compatibility, at least withrespect to cellular telephony, is likely to proceed on a networkimplementation basis in the near term, the parties agreed to workon methods and language for consumer education that would notdepend on equipment labeling.

February 1996



  1. CTIA believes 18 months from the FCC’s adoption of rules is a realistic frame for implementation of Phase I. The PSCs prefer the 12 months suggested in the Notice of Proposed Rulemaking.
  2. The FCC proposed that, 3 years after adoption of rules, ” the ALI information provided to the PSAP must include an estimate of the approximate location and the distance of the mobile unit from the receiving base station or cell site…” (Notice, Paragraph 50)
  3. The PSCs wish to emphasize that their abandonment of a 3-year intermediate deadline should not be taken to mean that no ALI improvements can or should be expected between Phase I and new Phase II (5 years from adoption of rules). To the contrary, the PSCs believe some vendors can meet now the new Phase II requirement discussed below, and that others will achieve this level of performance well in advance of 5 years.
  4. The dimension of altitude, or height above some ground reference, is not a part of this proposed requirement.
  5. The mathematical expression for RMS is found in Exhibit 1 hereto.
  6. This is illustrated by Exhibit 3, prepared by Dr. John Maloney of SKI, another vendor-participant in the docket.
  7. This range appears to represent the variance of the real from the theoretical, as discussed in the letter of January 3, 1996 from Louis Still of Associated Group to Bob Miller, Chair of the NENA Technical Issues Committee. (Exhibit 4)
  8. Rural or other thinly-populated areas may have system configurations which, without augmentation at special expense, would not deliver accurate ALI. Similarly, pockets obstructed by natural or artificial barriers might not be amenable to the techniques used to deliver ALI successfully in most of the serving area. In addition, carriers already have deployed, or will deploy, technologies for which there is no commercially available ALI solution. For example, no means now exists to provide ALI in tunnels where carriers must use coaxial cable (“leaky coax”) antennas to provide wireless service.
  9. The Wireless Industry has indicated that the relatively small additional expense involved in Phase I would not require advance adoption of public funding mechanisms.
  10. These examples are not meant to be prescriptive or exhaustive. The variety of state funding methods associated with wireline 9-1-1 and E9-1-1 is illustrated by a table and associated materials placed on the record of Docket 94-102 by the PSCs, pursuant to Section 1.1206 of the Rules, on October 11, 1995.

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