CEPT T CS 20-18 E-1981 Real Time Clock (ETSI ETR 202 1995)《实时时钟(ETSI ETR 202 1995)》.pdf

1、 CEPT T/CS*20-l*E AL m 2326434 0004543 2 m i TCS20-18 Page E 1 Recommendation T/CS 20-18 (Innsbruck 1981) REAL TIME CLOCK Recommendation proposed by Working Group T/WG 11 “Switching and Signalling” (CS) Text of the Recommendation adopted by the “Telecommunications” Commission: “The European Conferen

2、ce of Postal and Telecommunications Administrations, considering - that in accordance with the principles outlined in Recommendation T/CS 20-01 i, the ex1 lchange and network features which are required for the implementation of services and facilities should be identified and specified; - that in m

3、any existing exchanges in the European network, real time information is used for various functions and is likely to be required for several new services and facilities, recommends to the members of the CEPT the use of the following definition and arrangements for the feature real time clock.” O 1.

4、2. 3. 3.1. 3.2. 3.3. 3.4. 4. DEFINITION The real time clock feature is dened as the ability of an exchange to provide real time information. DESCRIPTION The real time clock feature of an exchange includes the functions required to identify the time at which an incident occurs or to recognise coincid

5、ence between a pre-dened time and real time. TECHNICAL CHARACTERISTICS The clock should maintain accuracy under all combinations of electrical load and ambient conditions. A tolerance of calendar day; minute; calendar month; hour; calendar year. In addition, up to N types of day may be required (the

6、 number N of types is for further study). UTILISATION The real time clock feature is used whenever reference to actual time is required and it is used in conjunction with other features on the following services: - malicious call identification; - automatic alarm call services; - printed record of c

7、harge information and charge announcement; - services where activation is carried out at prearranged times; - other administrative and maintenance services. Additionally, this feature will be used whenever it is required to print out the time at which a particular event occurred. It may also be used

8、 to switch tariff rates and for Cali charge calculations. Reference i Recommendation T/CS 20-01. Exchange and network features. Note: The studies on this series (T/CS 20) of Recommendations for the features in an analogue environment has now been terminated. A continuation of the studies has started with the aim to amend these existing features, where necessary, and to specify new featiires for the ISDN. These Recommendations will be gathered in a new series of Recommendations. O Edition of May 15, 1986 c-