WIRELINE
What is Wireline 9-1-1? ... 1 Class of Service ... 2 PBX ... 3 Foreign Exchange ... 4 TD-280A Processing ... 6What is Wireline 9-1-1?
Wireline or land-line refers to 9-1-1 calls placed from telephones that are hardwired at a particular address. In most areas of North America, citizens have basic or enhanced 9-1-1 service from their landline (or wireline) phones in their homes or workplaces.
o Basic 9-1-1 means that a call taker/dispatcher in the local Public Safety Answering Point (PSAP) associated with the central office of the caller's telephone system answers the call. There is no ability to route the call to the correct PSAP based on the jurisdiction of the caller. There is usually no ANI/ALI delivery; the emergency and its location are communicated by voice between the caller and the call taker.
o Enhanced 9-1-1 means the call is routed to the PSAP with jurisdiction for handling the call via a selective router (also called a tandem). The selective router looks up the Emergency Service Number (ESN) associated with the caller's telephone number (ANI). This ESN identifies the primary and secondary PSAPs that the call should be routed to based on jurisdiction for where the call is coming from. The PSAP also has premise equipment that accesses a second database which retrieves the ALI (caller's location information) and presents it along with the call back number to the call taker. This ANI/ALI information expedites dispatching of emergency help, even if the caller is unable to communicate where they are or the nature of the emergency.
Chapter
Figure 4-1. California E9-1-1 Network
Class of Service
The Class of Service designates the type of telephone service for the device originating the call _and is included on the call-taker's screen when a 9-1-1 call is delivered to a PSAP. The following are the basic Class of Service codes:
o RESD – Residential o BUSN - Business
o COIN – Coin operated phone o PAY$ – Pay phone
o CNTX – Centrex
o W911 – Wireless Phase I calls (more information on this is included in the Wireless 9-1-1 section)
o WPH2 - Wireless Phase II calls (more information on this is included in the Wireless 9-1-1 section)
o VoIP – Nomadic VoIP Subscriber (more information on this is included in the VoIP section)
o TLMA – Telematics (i.e. Onstar, SeriusXM (formerly Agero and ATX), Verizon Telematics).
Figure 4-2. Sample Wireline 9-1-1 ANI/ALI screen:
PBX
A Private Branch Exchange (PBX) is a private telephone network. Most medium-sized and larger companies use a PBX because it is much less expensive than connecting an external telephone line to every telephone in the organization. Many schools, banks, and government entities utilize a PBX.
telephone PBX switch, regardless of the location of the caller. The ANI displayed is typically the pilot number (usually defined as a 'blank' extension that goes nowhere and is used to locate a 'hunt group' or related group of extensions in a PBX system) and not the number to the telephone being used to dial 9-1-1.
Example: An emergency occurs at Patrick Henry High School at 4234 Middleton Rd in Anytown, CA. When a 9-1-1 call is placed from the school, the address displayed at the PSAP is the school district address of 1264 Other Street. The call back number displayed is the pilot number, not a telephone number that can be called back. One solution for PBX challenges is a service provided by the Telco that allows the PBX vendor to download PBX station address/location information to the 9-1-1 database. This service is called Private Switch 911 or PS/911 and is available at a cost from the local Telco. The arrangement is between the customer and the Telco. However, where PS/911 is not in place, the County Coordinator may want to contact the PBX owner and advise them of the PS/911 option. Document this contact in the Coordinator files for future reference.
Any misroutes received for a customer known to have PS/911 ALI service should be referred back to the PBX owner for correction. The Telcos have no ability to correct PBX station addresses. Due to this limitation, there is no need to enter an incorrect address discrepancy report for a PBX address correction.
For additional information on 9-1-1, see
http://www.nena.org/default.asp?page=911GeneralInfo or
http://transition.fcc.gov/pshs/services/911-services/Welcome.html
Foreign Exchange
NENA defines a foreign exchange as "a telephone line switched in an exchange or central office other than the exchange or central office area in which the telephone is located." To say it another way, it's a service that uses the phone number and dial tone from one Central Office while using the outside wires leading to the customer location from another Central Office. An example would be to install a phone number out of Tulelake, CA in Bend, OR. A customer will normally request this service to gain toll free access to the area they call the most that a number from their local Central Office would not provide.
Foreign Exchange (FX) 9-1-1 challenges
theory, you could have a phone number from Los Angeles serving a customer in New York. The only limitation to the service area is how much the customer is willing to pay for it. On the other hand, constructing a 9-1-1 system that would handle all possible FX links is cost prohibitive. Thankfully, FX service represents a very small percentage of the total phone service provided.
Verizon Database handling of FX services:
When FX service is established in a county the DBMC will determine: a) The selective router the FX phone number is routed through
b) The jurisdiction (i.e. phone company) that has authority over the FX npa/nxx and/or selective router. This will determine who should control the FX account.
c) The TN (ALI record) will be built in the E9-1-1 database to allow the following information to be displayed at the default PSAP responsible for the telephone switch involved:
• Customer Name: (The actual telephone subscriber’s name) • Address Number: (The actual telephone subscriber’s
address number)
• Street Name: FOREIGN EXCHANGE
• Community Name: (usually an abbreviated version of the county name)
• Location: (The actual street name and community the telephone subscriber is in – due to character limitations this may be abbreviated)
• ESN (assigned by the jurisdiction) Doing the above would:
1) Alert the 9-1-1 call taker that the call is coming from outside the normal serving area for the call back number.
2) Allow a default ESN and associated information to be displayed (and if applicable, default call routing to be performed) based on the telephone exchange (NPA/NXX combination)
To clarify a littler further, if the NPA/NXX originates (Local Exchange Routing Guide (Lerg) ) and terminates (subscriber’s location) within the same 9-1-1 Selective Router’s serving area, then the real address may be loaded into the ALI database which in turn will send the proper ESN and address to the proper Selective Router.
them that the caller isn’t served by their system). The PSAP would then transfer the call to the appropriate PSAP.
Figure 4-3. Example of a Foreign exchange ALI record:
TD-280A Processing
The TD-280A process is required to establish 9-1-1 network connectivity for CLECs. Upon receipt of the TD280A, the County Coordinator will review the document and:
o If necessary ask the CLEC to clarify the area of service within the rate area of the NXX code (prefix, first three digits of a 7-digit phone number) indicated on the TD-280A
o Test to confirm the 24 hours/7 day per week live-answer CLEC contact number is properly answered and subscriber information is available
o Assign the Default ESN (DESN), including the default agency name and the associated 10-digit telephone number
o Complete the County Coordinator contact name and telephone number section.
o Return the completed TD-280A to the requesting CLEC within five working days after receipt of the form. (Note: The County Coordinator’s processing time may be extended due to receipt of an inaccurate TD280A that may require additional information from the CLEC.)
More complete instructions can be found at
http://www.caloes.ca.gov/PSC/Pages/Publications/Forms.aspx
