CEPT T CD 01-02 E-1985 Engineering Requirements for a 300 Bit s Modem for Use on Public Telephone Type Circuits《在公共电话电路上使用的300比特 秒调制解调器工程要求》.pdf
《CEPT T CD 01-02 E-1985 Engineering Requirements for a 300 Bit s Modem for Use on Public Telephone Type Circuits《在公共电话电路上使用的300比特 秒调制解调器工程要求》.pdf》由会员分享,可在线阅读,更多相关《CEPT T CD 01-02 E-1985 Engineering Requirements for a 300 Bit s Modem for Use on Public Telephone Type Circuits《在公共电话电路上使用的300比特 秒调制解调器工程要求》.pdf(6页珍藏版)》请在麦多课文档分享上搜索。
1、I CEPT T/CD*OL-OZ*E 79 H 23264302998 O H I 69 Page E 1 Recommendation T/CD O1 -02 E (Ostende 1979, revised at Cannes 1983) concerning the engineering requirements for a 300 bit/s modem for use on public telephone type circuits Recommendation proposed by Working Group T/WG 10 “Data Communications” (C
2、D) Text of the revised Recommendation adopted by the “Teleconmtrrticntiols” Commission : “The Conference of European Post an Telecommunications Administrations, Considering - that Recommendation T/CD 01-01 contains the text of the Specifications of the general engineering requirements - that Working
3、 Group CD has studied under the auspices of question CD 1 the harmonization of voice band for data circuit terminating equipment for analogue and digital networks; modems for 300 bit/s. Recommends - that the attached Specification of engineering requirements for a 300 bit/s modem for use on the publ
4、ic telephone network as contained in Annex 1 to this Recommendation should be taken into account by all CEPT Administra- tions when implementation of such a piece of equipment is being planned by Administrations.” a Administrations are free to stipulate additional requirements, and also which of the
5、 optional requirements, if any, are to be provided. Note 1: It should be noted that this specification is subjected to continuing study and possible amendments. Note 2: The Annex is an integral part of the Recommendation. a _- y T/CD O1 -02 E Page 3 Annex 1 . Contents Section A . Basic requirements
6、5 1 . General. . 5 2 . Data signalling rates 5 3 . Interface., 5 4 . Modulation and coding . 6 5 . Scrambling 7 6.Timing 7 7 . Backward channel 7 8 . Line signal characteristics 7 9 . Ont of band interference . 7 10 . Performance requirements 7 11 . Testing and measuring requirements 7 12 . Interfac
7、e connector . 7 13 . Specific design requirements . 7 14 . Power supply 7 Section B . National network requirements . 8 15 . Environmental requirements . 7 Section C . Optional requirements . 8 1 . Operation on leased circuits . 8 2 . Receiver sensitivity . 8 3 . Specific design requirements . 8 Edi
8、tion of November 30. 1985 CEPT T/CD*OL-OZ*E 2326414 0003000 3 Interchange circuit Number Designation 102 103 Transmitted data 1 04 Received data Signal ground or common return 106 Ready for sending 107 Data set ready lOS/l 108/2 Data terminal ready 109 Connect data set to line Data channel received
9、line signal detector 125 Calling indicator 140 Loopback/maintenance test 141 Local loopback 142 Test indicator T/CD O1 -02 E Page 5 Public switched telephone network including ter- minals equipped for manual calling, manual an- swering, automatic calling, automatic answering (Note 1) X X X X X X (No
10、te 2) X (Note 2) X X X (Note 3) X (Note 3) X Section A. Basic requirements 1. GENERAL This paper describes the specifications of a full duplex modem to be used on the public telephone network. The modem must meet the requirements given in the Specification of the general engineering requirements (Re
11、commendation T/CD 01-01) and in this specification. It shall also comply with CCITT Recommenda- tion V.24/V.28. 2. DATA SIGNALLING RATES The modem shall use binary frequency modulation and provide facilities for the simultaneous transmission and reception of data at rates up to 300 bit/s over two wi
12、re presented circuits. No coding restrictions shall be imposed on the data signals. However satisfactory operation with modem at a modulation rate of 200 baud according to CCITT Recommendation V.21 should be ensured. 3. INTERFACES 3.1 3.2. Electrical characteristics of interchange circuits The elect
13、rical characteristics of the above mentioned interchange circuits are given in the relevant paragraph of the general engineering requirements (Recommendation T/CD 01-01), complying with CCITT Recom- mendation V.28. 3.3. Automatic answering The modem shall be provided with automatic answering facilit
14、ies according to the relevant part of the general engineering requirements (Recommendation T/CD O1 -0 1). Edition of November 30, 1985 r CEPT T/CD*OL-OZ*E = 2326414 0003001 5 T/CD O1 -02 E Page 6 3.4. 3.5. 3.6. 4. 4.1. 4.2. 4.3. 4.4. 4.5. Response times Definition of response times of interchange ci
15、rcuits 106 und 109: Circuit 109 response times are the times that elapse between the connection or removal of a tone to or from the modem receive line terminals and the appearance of the corresponding ON or OFF condition on circuit 109. The test tone should have a frequency corresponding to the char
16、acteristic frequency of binary 1 and be derived from a source with an impedance equal to the nominal input impedance of the modem under test. The level of the test tone should fall into the level range between 1 dB above the actual threshold of the received line signal detector and the maximum admis
17、sible level of the received signal. At all levels within this range the measured response times shall be within the specified limits. Circuit 106 response times are the times from the connection of an ON or OFF condition on: - circuit 105 (where it is provided, see section B) to the appearance of th
18、e corresponding OFF or ON - circuit 109 (where circuit 105 is not provided) to the appearance of the corresponding ON or OFF Response times of circuits 106 and 109 Response times : 106 OFF to ON 20-50 ms (see Note 1) ON to OFF 2 ms. 109 OFF to ON 20 ms (see Note 1) ON to OFF 20-80 ms (see Note I) No
19、te 1: These times are used on leased point-to-point networks without alternate voice-data facilities and on leased multipoint facilities. Note 2: These times are used on PSTN and on leased point-to-point circuits with alternate voice-data. condition on circuit 106; condition on circuit 106. 400-1,00
20、0 ms (see Note 2). 300-700 ms (see Note 2). 20- 80 ms (see Note 2). Receiver sensitivity Threshold greater than -43 dBm circuit 109 ON -48 dBm circuit 109 OFF. The condition of circuit 109 for levels between -43 dBm and -48 dBm is not specified except that the signal detector shall exhibit a hystere
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