1、ITU-T RECUN*V.LO 93 4862591 058q528 T4b H INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOM MUN I CATION STANDARDIZATION SECTOR OF ITU DATA COMMUNICATION OVER THE TELEPHONE NETWORK v.l o (03193) ELECTRICAL CHARACTERISTICS INTERCHANGE CIRCUITS OPERATING AT DATA SIGNALLING RATES NOMINALLY UP TO 100
2、kbits FOR UNBALANCED DOUBLE-CURRENT ITU-T Recommendation V.1 O (Previously “CCIlT Recommendation”) ITU-T RECMN+V-LO 93 m 4862593 0584529 982 m FOREWORD The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the Intemational Telecom- munication Union. The ITU-T is responsibl
3、e for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, established the topics for study by the ITU-
4、T Study Groups which, in their turn, produce Recommendations on these topics. ITU-T Recommendation V.10 was revised by the ITU-T Study Group XVII (1988-1993) and was approved by the WTSC (Helsinki, March 1-12, 1993). NOTES 1 As a consequence of a reform process within the International Telecommunica
5、tion Union (ITU), the CCIT ceased to exist as of 28 February 1993, In its place, the ITU Telecommunication Standardization Sector (ITU-T) was created as of 1 March 1993. Similarly, in this reform process, the CCIR and the IFRB have been replaced by the Radiocommunication Sector. In order not to dela
6、y publication of this Recommendation, no change has been made in the text to references containing the acronyms “CCITT, CCIR or IFRE!” or their associated entities such as Plenary Assembly, Secretariat, etc. Future editions of this Recommendation will contain the proper terminology related to the ne
7、w ITU structure. 2 telecommunication administration and a recognized operating agency. In this Recommendation, the expression “Administration” is used for conciseness to indicate both a O ITU 1994 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any me
8、ans, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. ITU-T RECNNaV-LO 73 48b259L 0584530 bT4 1 2 3 4 5 6 7 8 9 10 11 12 CONTENTS Introduction Field of application Symbolic representation of an interchange circuit . Generator polarities and
9、receiver significant levels . 4.1 Generator 4.2 Receiver Generator 5.1 Output impedance . 5.2 Static reference measurements 5.3 Generator output rise-time measurement Load . 6.1 Characteristics . 6.2 Receiver input voltage - Current measurements 6.3 DC input sensitivity measurements 6.4 Input balanc
10、e test Environmental constraints Circuit protection . Category i and category 2 receivers Signal common return Detection of generator power-off or circuit failure Measurements at the physical interchange point 12.1 Listing of essential measurements 12.2 Listing of optional measurements . Annex A . C
11、ompatibility with other interfaces . Compatibility of Recommendation V . 10 and Recommendation V . 1 1 interchange circuits in the same interface . Recommendation V . 10 interworking with Recommendation V . 11 Recommendation V.10 interworking with Recommendation V.28 Annex B - Considerations for coa
12、xial cable applications - V.10 COAXIAL Appendix I - Waveshaping . Appendix II - Cable Guidelines Reference . A . i A.2 A.3 Page 1 1 2 2 2 2 3 3 4 6 7 7 7 7 8 9 9 10 11 12 12 12 13 13 13 13 13 15 16 17 18 Recommendation V.10 (03/93) i ITU-T RECMN*V.LO 93 I 4862591 0584533 530 I Recommendation V.10 EL
13、ECTRICAL CHARACTERISTICS FOR UNBALANCED DOUBLE- CURRENT INTERCHANGE CIRCUITS OPERATING AT DATA SIGNALLING RATES NOMINALLY UP TO 100 kbit/sl) 2) (Geneva, 1976; amended at Geneva, 1980, at Melbourne, 1988 and Helsinki, 1993) 1 Introduction This Recommendation deals with the electrical characteristics
14、of the generator, receiver and interconnecting leads of an unbalanced interchange circuit employing a differential receiver. In the context of this Recommendation an unbalanced interchange circuit is defined as consisting of an unbalanced generator connected to a receiver by an interconnecting lead
15、and a common return lead. Annexes and appendices are provided to give guidance on a number of application aspects as follows: Annex A Annex B Appendix I Waveshaping Appendix II Cable guidelines NOTE - Generator and load devices meeting the electrical characteristics of this Recommendation need not o
16、perate over the entire data signalling rate range specified. They may be designed to operate over narrower ranges to satisfy specific requirements more economically, particularly at lower data signalling rates. The interconnecting cable is normally not terminated, but the matter of terminating coaxi
17、al interconnecting cable is dealt with in Annex B. Where the interchange circuit incorporates the special provisions for coaxial applications with cable termination this shall be referred to as “complying with Recommendation V. 10 (COAXIAL)”. Reference measurements are described which may be used to
18、 verify certain of the recommended parameters but it is a matter for individual manufacturers to decide what tests are necessary to ensure compliance with this Recommendation. Compatibility with other interfaces Considerations for coaxial cable applications - V. 10 COAXIAL 2 Field of application The
19、 electrical characteristics specified in this Recommendation apply to interchange circuits operating with data signalling rates up to 100 kbit/s. This Recommendation is not intended to apply to equipment implemented in discrete component technology, for which the electrical characteristics covered b
20、y Recommendation V.28 are more appropriate. Typical points of application are illustrated in Figure 1. Whilst the unbalanced interchange circuit is primarily intended for use at the lower data signalling rates, its use should be avoided in the following cases: 1) 2) 3) where the interconnecting cabl
21、e is too long for proper unbalanced circuit operation; where extraneous noise sources make unbalanced circuit operation impossible; where it is necessary to minimize interference with other signals. Whilst a restriction on maximum cable length is not specified, guidelines are given with respect to c
22、onservative operating distance as a function of data signalling rates (see Appendix II). *) This Recommendation is also designated as X.26 in the X-Series Recommendations. 2, Signalling rates above the suggested 100 kbit/s may also be employed, but the maximum suggested operating distances should be
23、 shortened accordingly (see Figure 11-1). Recommendation V.10 (03/93) 1 T1400040-93/dOl FiGRE lN.10 Typical applications of unbalanced interchange circuits 3 Symbolic representation of an interchange circuit See Figure 2. For data transmission applications, it is commonly accepted that the interface
24、 cabling is provided by the DE. This introduces the line of demarcation between the DTE plus cable and the DCE. This line is also called the interchange point and physically implemented in the form of a connector. The applications also require interchange circuits in both directions. This leads to a
25、n illustration as shown in Figure 3. 4 Generator polarities and receiver significant levels 4.1 Generator The signal conditions for the generator are specified in terms of the voltage between output points A and C shown in Figure 2. When the signal condition O (space) for data circuits, or ON for co
26、ntrol and timing circuits, is transmitted the output point A is positive with respect to point C. When the signal condition 1 (mark) for data circuits, or OFF for control and timing circuits, is transmitted the output point A is negative with respect to point C. 4.2 Receiver The receiver significant
27、 levels are shown in Table 1, where Vk and VB are respectively the voltage at points A and B relative to point C. 2 Recommendation V.10 (0393) ITU-T RECMN*V-LO 93 48b259L 0584533 303 Interconnecting 1 Y _* Load - Generator cable .- -4 Cable termination (see Note 3) Receiver A- conductor _A - Stgnal
28、.-: b u c -i *This terminating resistor is only used with “V.l-COAXIAC, see Annex B. Ve, Generator output vdtage V, Ground potential difference Z, Cable termination impedance A Generator active interchange point C Generator common return point A Load active interchange point B Load common return poi
29、nt C Receiver zero reference point NOTES 1 interconnecting cable, are defined at the “generator interchange point”. The electrical characteristics to which the receiver must respd are defined at the “load interchange point”. 2 The connection of the signal common return is dealt with in 10 below. Poi
30、nts C and C may be connected to protective ground if required by national regulations. 3 The interconnecting cable is normally not terminated. The termination of coaxial interconnecting cable is dealt with in Annex B. Two interchange points are shown. The output characteristics of the generator, exc
31、luding any FIGURE 2/V. 10 Symbolic representation of an unbalanced interchange circuit 5 Generator3) 5.1 Output impedance The total dynamic output impedance of the generator shall be equal to or less than 50 ohms. 3, For test purposes other than specified in this Recommendation (e.g. signal quality
32、measurement), a transmitter test load of 450 ohms may be used. Recommendation V.10 (03/93) 3 ITU-T RECMN*V-LO 93 4862591 0584534 24T E VA1 - VE* -0.3 v (Connector) (See Note 3) VA* - VB* Z +0.3 V . B Data circuits Control and timing circuits l DTE common return 1 O OFF ON I I I c 1 1 Signal ground C
33、LC rn - demarcation T140006Q93M03 NOTES 1 signal ground conductor. 2 regulations require. 3 application. IS0 specifies, for data transmission over telephone type facilities, a 37-pin connector in IS0 4902. The zero volt reference interchange points C may be interconnected via the Signal ground may b
34、e further connected to external protective ground if national The type of connector with this electrical characteristic specification depends on the FIGURE 3N.10 Practical representation of the interface 5.2 Static reference measurements The generator Characteristics are specified in accordance with
35、 measurements illustrated in Figure 4 and described in 5.2.1 to 5.2.4. 4 Recommendation V.10 (03/93) ITU-T RECMN*V*LO 93 I 4862593 0584535 38b 5.2.1 Open circuit measurement See Figure 4a). The open circuit voltage measurement is made with a 3900-ohm resistor connected between points A and C. In bot
36、h binary states, the magnitude of the signal voltage (Vo) shall be equal to or greater than 4.0 volts but not greater than 6.0 volts. 5.2.2 Test termination measurement See Figure 4b). With a test load of 450 ohms connected between output points A and C, the magnitude of the output voltage (V,) in b
37、oth binary states shall be equal to or greater than 0.9 of the magnitude of Vo. 5.2.3 Short-circuit measurement See Figure 4c). With the output points A and C short-circuited the current (Zs) flowing through point A in both binary states shall not exceed 150 milliamperes. 5.2.4 Power-off measurement
38、s See Figure 4d). Under power-off condition, with a voltage ranging between +0.25 volt.and -0.25 volt applied between the output point A and point C, the magnitude of the output leakage current (I,) shall not exceed 100 microamperes. -I 8 b) Test termination measurement iVti 2 0.9 I Vol ,= 450* ohms
39、 C Y 1 J * For coaxial cable applications, see Annex B. FIGURE 4N.10 Generator parameter reference measurements Recommendation V.10 (03/93) 5 ITU-T RECNN*V=LO 93 = Y862591 058q53b 012 m 5.3 Generator output rise-time measurement See Figure 5. Vss Vdiage ddfmce between steady state signai conditions
40、tr- i+ T1400080-93Id05 FIGURE YV.10 Generator output rise-time measurement 5.3.1 Waveform The measurement will be made with a resistor of 450 ohms connected between points A and C. A test signal, with a nominal signal element duration tb and composed of alternate ones and zeros, shall be applied to
41、the input. The change in amplitude of the output signal during transitions from one binary state to the other shall be monotonic between 0.1 and 0.9 of Vss. 5.3.2 Waveshaping Waveshaping of the generator output signal shall be employed to control the level of interference (near-end crosstalk) which
42、may be coupled to adjacent circuits in an interconnection. The rise time (t,) of the output signal shall be controlled to ensure the signal reaches 0.9 V, between O. 1 and 0.3 of the duration of the unit interval (tb) at signalling rates greater than 1 kbit/s, and between 100 and 300 microseconds at
43、 signalling rates of 1 kbit/s or less. The method of waveshaping is not specified but examples are given in Appendix I. 6 Recommendation V.10 (03/93) ITU-T RECMN*V*LO 73 W 4862.571 0584537 T59 IIpI 6 Load 6.1 Characteristics The load consists of a receiver (R) as shown in Figure 2. The electrical ch
44、aracteristics of the receiver are specified in terms of the measurements illustrated in Figures 6, 7 and 8 and described in 6.2, 6.3 and 6.4 below. A circuit meeting these requirements results in a differential receiver having a high input impedance, a small input threshold transition region between
45、 -0.3 and +0.3 volts differential, and allowance for an internal bias voltage not to exceed 3 volts in magnitude. The receiver is electrically identical to that specified for the balanced receiver in Recommendation V. 1 1. 6.2 See Figure 6. Receiver input voltage - Current measurements With the volt
46、age Vja (or Vjb) ranging between -10 volts and +10 volts, while Vib (or Vi,) is held at O volt, the resultant input current Zia (or lib) shall remain within the shaded range shown in Figure 6. These measurements apply with the power supply of the receiver in both the power-on and power-off condition
47、s. c r- FIGURE 6N.10 Receiver input voltage-current measurements 6.3 DC input sensitivity measurements See Figure 7. Over the entire common-mode voltage (Vem) range of +7 volts to -7 volts, the receiver shall not require a differential input voltage (Vi) of more than 300 millivolts to assume correct
48、ly the intended binary state. Reversing the polarity of Vi shall cause the receiver to assumexhe opposite binary state. The maximum voltage (signal plus common-mode) present between either receiver input and receiver ground shall not exceed 10 volts nor cause the receiver to malfunction. The receive
49、r shall tolerate a maximum differential voltage of 12 volts applied across its input terminals without being damaged. In the presence of the combinations of input voltages Vi, and Vib specified in Figure 7, the receiver shall maintain the specified output binary state and shall not be damaged. NOTE - Designers of equipment should be aware that slow signal transitions with noise present may give rise to instability or oscillatory conditions in the receiving equipment; therefore, appropriate techniques should be implemented to prevent such behaviour. For
