1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 6 G0BISTELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU$!4!G0G0#/-5.)#!4)/./6%2G0G04(%G0G04%,%0(/.%G0G0.%47/2+%,%#42)#!,G0#(!2!#4%2)34)#3G0G0&/23).,%G13#522%.4G0G0).4%2#(!.%G0G0#)2#5)4353).G0G0/04/#/50,%23)45G134G0G0RecommendationG0G06 G0BIS(Extract from the
2、 “LUEG0“OOK)NOTES1 ITU-T Recommendation V.31 bis was published in Fascicle VIII.1 of the Blue Book. This file is an extractfrom the Blue Book. While the presentation and layout of the text might be slightly different from the Blue Book version,the contents of the file are identical to the Blue Book
3、version and copyright conditions remain unchanged (see below).2 In this Recommendation, the expression “Administration” is used for conciseness to indicate both atelecommunication administration and a recognized operating agency. ITU 1988, 1993All rights reserved. No part of this publication may be
4、reproduced or utilized in any form or by any means, electronic ormechanical, including photocopying and microfilm, without permission in writing from the ITU.Fascicle VIII.1 - Rec. V.31 bis 1Recommendation V.31 bisFascicle VIII.1 - Rec. V.31 bisELECTRICAL CHARACTERISTICS FOR SINGLE-CURRENTINTERCHANG
5、E CIRCUITS USING OPTOCOUPLERS(Malaga-Torremolinos, 1984)1 GeneralIn general, the electrical characteristics specified in this Recommendation apply to interchange circuitsoperating at data signalling rates up to 75 bit/s, which have been covered in Recommendation V.31, and also tointerchange circuits
6、 operating at data signalling rates up to 1200 bit/s.The electrical characteristics are specified to provide compatibility with existing equipment according toRecommendation V.31 which meet the voltage and current values given in Table 1/V.31 bis. The resistance valuesdefined in Recommendation V.31
7、are converted into current and voltage values to meet the optocouplers requirements.Each interchange circuit consists of two conductors (go and return leads) which are electrically insulated fromeach other and from all other interchange circuits. A common return lead can be assigned to several inter
8、change circuitsof a group.2 Equivalent circuit of interfaceFigure 1/V.31 bis shows the equivalent interchange circuit, together with the electrical characteristics laid downin this Recommendation. Some electrical characteristics vary depending upon whether the signal receive side is locatedin the da
9、ta circuit-terminating equipment (DCE) or in the data terminal equipment (DTE). This fact is specially referredto below.3 Signal sourceThe signal source must be isolated from ground or earth irrespective of whether it is located within the datacircuit-terminating equipment or within the data termina
10、l equipment.If the signal receive side is in the data circuit-terminating equipment, the insulation resistance in the ON or OFFcondition measured from either leg to ground or to any other interchange circuit shall not fall below 5 megohms and thecapacitance measured between the same points shall not
11、 exceed 1000 picofarads.Irrespective of the above, the following specifications apply to the signal source.3.1 Internal resistance of signal source R1, R0The d.c. resistance of the signal source in the ON (or 1) condition R1depends on Vs , Vrand I1(seeFigure 1/V.31 bis). The d.c. resistance of the s
12、ignal source in the OFF (or 0) condition R0depends on Vrand I0(seeFigure 1/V.31 bis).3.2 Current at the interface I0The current I0, which represents the reverse current of the optocouplers in the OFF condition, should not exceed10 A (see Figure 1/V.31 bis).3.3 Capacitance of signal sourceThe capacit
13、ance of the signal source Cgincluding that of the interface cable, measured at the interface (seeFigure 1/V.31 bis), should not exceed 2500 pF.2 Fascicle VIII.1 - Rec. V.31 bis4 Signal receive side4.1 Signal receive side in the DCEThe signal receive side in the DCE can be floating or connected to gr
14、ound at any single point.4.1.1 Open circuit voltage of the signal receive side VrThe open circuit voltage Vron the signal receive side of the DCE, measured at the interface (seeFigure 1/V.31 bis), should not fall below 3 V and should not exceed 25 V. The polarity of Vrhas to be chosen for thecurrent
15、 direction DTE to DCE in the go lead and DCE to DTE in the return lead.4.1.2 Current at the interface I1The current I1supplied by the receive side in the DCE should not fall below 0.1 mA and should not exceed5 mA, when measured at the interface in the ON (or 1) condition.4.1.3 Voltage at the interfa
16、ce VsThe voltage at the interface Vs, measured between the go and return leads in the ON (or 1) condition, should notexceed 1 V.Fascicle VIII.1 - Rec. V.31 bis 34.1.4 Internal resistance of signal receive side RrThe internal resistance Rrof the signal receive side of the DCE results from the limits
17、for the open circuitvoltage Vrof the signal receive side and the current I1at the interface, which are specified under 4.1.1 and 4.1.2above.Even if Rrhas an inductive component, the voltage at the interface should not exceed the maximum of 25 Vspecified under 4.1.1 above.4.1.5 Capacitance of signal
18、receive side CrThe capacitance of Cr , of the signal receive side in the DCE, including the capacitance of the cable up to theinterface (see Figure 1/V.31 bis), is not specified. It is only necessary to ensure that the signal receive side workssatisfactorily, allowing for the capacitance of the sign
19、al source Cg.4.2 Signal receive side in the DTEThe signal receive side in the DTE can be connected to ground at any single point.4.2.1 Open circuit voltage of the signal receive side VrThe open circuit voltage Vrof the signal receive side of the DTE, measured at the interface (see Figure 1/V.31bis),
20、 should not fall below 3 V and should not exceed 25 V. The polarity of Vrhas to be chosen for the current directionDTE to DCE in the go lead and DCE to DTE in the return lead.4.2.2 Current at the interface I1The current I1,supplied by the signal receive side in the DTE, should not fall below 0.1 mA
21、and should notexceed 15 mA, when measured at the interface (see Figure 1/V.31 bis), in the ON (or 1) condition.4.2.3 Voltage at the interface VsThe voltage at the interface Vs, measured between the go and return leads in the ON (or 1) condition, should notexceed 1.5 V.4.2.4 Internal resistance of si
22、gnal receive side RrThe internal resistance Rrof the signal receive side of the DTE results from the limits for the open circuitvoltage Vrof the signal receive side and the current I1at the interface, which are specified under 4.2.1 and 4.2.2above.4.2.5 Capacitance of signal receive side CrThe capac
23、itance of Crof the signal receive side in the DTE including the capacitance of the cable is notspecified. It is only necessary to ensure that the signal receive side works satisfactorily, allowing for the capacitance ofthe signal source Cg.5 Signal allocationTable 1/V.31 bis shows allocations of digital signals for data, control and timing circuits.4 Fascicle VIII.1 - Rec. V.31 bisTABLE 1/V.31 bis0.1 mA I1 5 mA(15 mA)Vs 1 V (1.5 V)I010 AData circuits 1 condition 0 conditionControl and timing circuits ON condition OFF condition
