Call Charging of Digital Telephone Switching System


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Document Category Engineering
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In the present Company network, a combination of Local Automatic Message Accounting (LAMA) and Periodic Pulse Metering (PPM) systems are used for charging of calls. LAMA is used in the Stored Program Control (SPC) digital switching exchanges. All digital local exchanges shall be equipped with LAMA facilities for charging of local calls, toll calls, and international calls as well as voice and non-voice calls. The exchanges shall have the capability to generate multimetering pulses locally, whenever it might be necessary, for local calls made within the unit fee area.

Call Charging of Digital Telephone Switching System

Commentary Note:
A Centralised Automatic Message Accounting (CAMA) system is more economical and preferable, than the presently used LAMA system, for all local areas where a CAMA facility can serve two or more CO exchanges within the Saudi Aramco telecommunications network.

5.32.1 Tariffs and Free-of-charge Calls

The tariffs, which are applied for each individual local charging area to all other local charging areas in different zones, are decided by the dialed digits. Tariffs can be changed via a “change procedure” during normal traffic. These changes should be verified off-line prior to implementation on the digital switch. The exchanges shall allow for charge-free calling to specified lines.
5.32.2 Operational Test Features for Call Counting and Registration Systems
The exchanges shall be equipped with software and hardware terminals necessary to make operational tests on the registration systems and to charge tariffs by modifying data during normal exchange activity, without disturbing ongoing traffic. The call counting and registration system shall allow for verification and testing of tariff changes before they are put into effect.
5.32.3 Automatic Number Identification (ANI) of Calling Subscriber
The exchanges shall be equipped with Automatic Number Identification (ANI). The directory number corresponding to A-subscriber, his interurban prefix and category shall be available at any moment during the establishment of a call, so that it may be retransmitted if requested. The manufacturers shall state the number of different A-subscriber categories that may be stored and retransmitted as responses to a request made by another exchange using Multi Frequency Code (MFC) register signaling. They shall also state if the categories depend on the system’s signaling capacity and if it will be possible to expand the number of category groups in the future.

5.32.4 Storage of Data

The call-charging data stored in the buffer memory area of the local exchange shall be periodically transferred to a magnetic tape, or similar arrangement, in the same exchange. The magnetic tape unit used to store billing data, shall be duplicated. The exchange shall have the capability to transfer call charging data to an operation and maintenance center via a data link. It is essential that the buffer memory area retain (protect) its information until it can be transferred to the storage tape.

5.32.5 Local Automatic Message Accounting (LAMA) System

The following features shall be included in the Local Automatic Message Accounting (LAMA) system of the exchanges:

10th of minute).
 Duration of call (hour, minute, 10th of minute).
2. Long Distance Dialing calls (LDD) and International Direct Distance Dialing calls (IDDD) for combined local and transit:
 Type of call.
 Calling number.
 Called number (dialed digit).
 Date (Julian).
 Time of called party answer (hour, minute, 10th of minute).
 Duration of call (hour, minute, 10th of minute).
 Date change over (midnight) identification.
5.32.6 Charging Observation
The exchange shall enable billing processes to be checked, both on a routine basis and on a demand basis, to respond to subscriber

complaints. The following information shall be provided to enable Saudi Aramco to inform subscribers about the correctness of their bills:
a) Date/time of origin of each call, outgoing and incoming.
b) Called number and time at which each call was placed.
c) Time at which subscriber answered.
d) Duration of call.

5.32.7 Charging Statistics

It is required that the charging system shall be equipped to provide charging statistics, for planning purposes and tariff adjustments. Recorded data shall include the number of calls and the number of meter-pulses registered for those calls during a given period of time.
Activation and deactivation of the gathering of charging statistics shall be initiated by command. When a recording is ended, recorded data shall be output automatically. It shall be possible to output data on a printer/display or on a magnetic tape device, or to send data directly over a data link to a computer center.
The data to be printed out shall consist of the following:
a) Tariff of each call type.
b) Date and time when the recorder was started.
c) Start and stop time for each time period.
d) Number of the calls and/or number of the meter pulses for each time period for each call type.

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