4 Pa. Code § 120b.104
ALI-Automatic Location Identification-A feature which displays a name and address associated with the telephone number from which the call originated to the PSAP on customer premises equipment.
ANI-Automatic Number Identification-A feature by which the telephone number from which the call originated is forwarded to the compatible customer premises equipment.
APCO-Associated Public Safety Communicate Officers, Inc.-A not-for-profit organization incorporated to develop and foster the progress of the art of public safety communications whose sole purpose is to promote greater correlation of the communications activities of towns, cities, counties, State and Federal agencies, and represent the agencies before the Federal Communications Commission and other regulatory bodies.
Alternative routing-A feature of the CPE that allows the 911 calls to be routed to a designated alternate location if the following conditions exist:
Answering position-An appropriately equipped location within a PSAP that is used to receive incoming 911 calls.
Audible signal-A sound that indicates an incoming 911 call.
Average busy hour-The 1-hour period during the day statistically shown over time to be the hour in which the most emergency telephone calls are received.
Called party hold-A feature where the attendant retains control of the circuit despite the switchhook condition of the originating station. By remaining off-hook or placing the call on hold, control of the circuit is maintained.
Call party trunk hold-A feature designed to manage multiple calls where the answering point has the capability to place the calls on hold. This feature is required only where CPE is utilized.
Call-progress-An audible (ringing) or visual (lighted) indication of the 911 call status to the call taker.
Central office transfer-
Emergency ringback-A feature that if a 911 caller abandons a call, before information necessary to provide aid is received, the PSAP attendant can activate this central office feature and ring the "on-hook" station which originated the call.
Forced disconnect-A circuit that is automatically disconnected at the central office despite the switchhook condition of the calling party.
Idle circuit tone application-An audible signal that informs the PSAP attendant of the status of the line being monitored. Two types of tones are applied to a line under the following conditions:
Immediate/splash ringing-A feature whereby incoming 911 calls are automatically directed to the first available answering position. This allows the caller access to the first available operator and prevents in most cases a busy signal or call hold. Incoming calls may be transferred from station to station within a PSAP, or may be transferred from PSAP to PSAP.
Routing profiles-A set of procedures that details how PSAPs are notified in the event of circuit disruptions so corrective actions can be taken in a timely manner. Network providers should maintain current routing profiles and ensure that disruption of any circuit element which involves 911 trunking is detected within a reasonable amount of time.
Selective routing/transfer-A feature that routes a 911 call to the predesignated PSAP based upon the identified number of the calling party. Selective transfer provides the PSAP with the ability to transfer an incoming call to another responding agency by depressing a single button labeled with the type of agency; for example, "FIRE," on the associated customer premises equipment.
Switchhook status-A feature that indicates an audible or visual, or both, signal if the station originating the 911 call returns to an off-hook status.
Tandem trunking-An arrangement where a telephone line connection has one or more intermediate switching points which are required or permitted before reaching the final destination. This usually occurs on a controlled dial pulse basis.
TDD/TTY-A telecommunication device for the hearing and speech impaired.
Number of Access Lines in End Central Office
Divided by 1,000
Multiplied By
Length of the Average 911 Call in Seconds (90)
Multiplied By
Busy Hour Traffic (Range 10%-15%)
Multiplied By
Calls per 1,000 Access Lines (2.5)
Divided By
100 (to convert Calling Seconds to CCS)
Equals
CCS to be carried by 911 Trunk Group
| AL x ACL x BHT x CPT |
| 1,000 x 100 |
AL-Access Lines-Obtained from telephone company
ACL-Average Call Length-Assume 90 seconds
BHT-Busy Hour Traffic-Assume Range of between 10%-15%
CPT-Calls per 1,000 access lines per day-Assume 2.5
CCS-Hundred calling seconds
Using the formula in this subparagraph, CCS data determines the number of trunks from the following table with each end office having a minimum of two 911 trunks to the control central office.
| TRUNK LOADING CAPACITY | |
| Grade of Service 1 delay in 1,000 | |
| Trunks | Will Carry CCS |
| 2 | 1.6 |
| 3 | 6.9 |
| 4 | 15 |
| 5 | 27 |
| 6 | 40 |
| 7 | 55 |
| 8 | 71 |
| 9 | 88 |
| 10 | 107 |
4 Pa. Code § 120b.104
The provisions of this § 120b.104 amended under the Emergency Management Service Code, 35 Pa.C.S. § 7313.
This section cited in 4 Pa. Code § 120b.103 (relating to development of county plan); and 4 Pa. Code § 120c.112 (relating to right to enter and inspect).