1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 5 TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITU4%,%2!0(G0G037)4#().3).!,).G0G0/6%2G0G02!$)/G0G0!.$G0G0-5,4)0,%8%$#(!%,32%15)2%-%.43G0G0(b) that it is essential to transmit the full range of telex signals for types A, B, C and D signalling;unanimously decl
2、aresthat the following requirements for telex and gentex operation should be met by code- and speed dependenttime division multiplex systems conforming to Recommendation R.101.1 Transmission of type A (control) signals shall be accomplished within the tolerances specified in Table 1/U.25.2 Transmiss
3、ion of type B (control) signals shall be accomplished within the tolerances specified in Table 2/U.25.3 Transmission of type C signals shall be accomplished in accordance with Table 3/U.25.4 Transmission of type D signals shall be accomplished in accordance with Recommendation U.12.5 Each of the fol
4、lowing modes of bothway telex signalling shall be capable of being accomplished on a singlecircuit:a) type A in one direction and type B keyboard in the other;h) type A in one direction and type B dial in the other;c) type B keyboard in one direction and type B dial in the other;d) type A in both di
5、rections;c) type B dial in both directions;f) type B keyboard in both directions;g) type C to Table 1/U.11;h) type C to Table 2/U.11;i) type C to Table 3/U.11.6 A single terminal shall be capable of handling any of the signalling combinations shown in 5 above and atleast five of them simultaneously.
6、7 The nominal pulse duration (other than dial pulses) shown in Tables l/U.25, 2/U.25 and 3/U.25 for Signaltransmitted to telex have a 3 ms tolerance except where otherwise indicated.2 Fascicle VII.2 - Rec. U.25TABLE 1/U.25Type A signallingSignallingconditionSignal received from telex(Recommendation
7、U.1)Signal on aggregate path(Note 1)Signal transmittedto telexFree line Continuous A polarity onboth signalling pathsContinuous A polarity Continuous A polarityCall Inversion to Z polarity onforward signalling pathInversion to Z polarity Inversion to Z polarity (within 50 ms of inversion in column 2
8、) (Note 2)Call-confirmation Inversion to Z polarity onbackward signalling pathAs for call As for callProceed to select Teleprinter signals (semi-automatic) or an intervalof polarity for not lessthan 100 ms folowed by40 8 ms of A polarity onthe backward pathTeleprinter signals (semi-automatic) or no
9、lessthan 5 bits of Z polarity followed by 2 bits ofA polarityTeleprinter signals (semi-automatic) orZ polarity for no less than 97 msfollowed by 40 ms of A polaritySelection Teleprinter signals onforward pathTeleprinter signals Teleprinter signalsCall-connect Teleprinter signals or150 ms ( 11 ms) pu
10、lseof A polarity followed bya minimum of 2 s ofZ polarity on the back-ward pathTeleprinter signals or 7 or8 bits of A polarity fol-lowed by a minimum of102 bits of Z polarityTeleprinter signals or 140or 157 ms pulse of A polarityfollowed by a minimum 1.997 s ofZ polarityService signals Teleprinter s
11、ignals onbackward pathfollowed by a clearingsignalTeleprinter signalsfollowed by continuousA polarityTeleprinter signals followed by con-tinuous A polarityClear Inversion to A polarity oneither signalling pathInversion to A path Inversion to A polarityClear-confirmation Inversion to A polarityin opp
12、osite direction toclear after a delay of350-1500 ms followingreceipt of the clear signalAs for clear As for clearAutomatic retest Z polarity for 2 s 10%followed by A polaritylasting at least 58 s 10%repeated91-112 bits of Z polarityfollowed by at lest2665 bits of A polarity1.782-2.194 s of Z polarit
13、y followed by at least 52.188 s of A polarityFor notes, see Table 3/U.25.Fascicle VII.2 - Rec. U.25 3TABLE 2/U.25Type B signallingSignallingconditionSignal receivedfrom telexSignal on aggregate path(Note 1)Signal transmittedto telexFree line As for type A As for type A As for type ACall As for type
14、A As for type A As for type ACall confirmation 17-35 ms pulse ofZ polarity on the back-ward path returned within150 ms of receipt of thecall signal1-2 bits of Z polarity 20-40 ms pulse of Z polarityProceed-to-select As for call-confirmation.the interval of A polarityseparating the pulses willbe 100
15、ms minimumInterval of not less than5 bits of A polarityfollowed by 1-2 bits ofZ polarityAs for call-confirmation. The intervalbetween the pulses to be nominally100 ms minimumSelection signals Teleprinter signals or dialpulses having the followinglimits: Speed = 9-11 pps,Z: A ratio = 1 : 1.2 to1 : 1.
16、9 (Recommen-dation U.2)Teleprinter signals or dialpulses, where eachA polarity is transmittedas 2-4 bits and eachZ polarity as at least 1 bit,the mean speed of pulsingbeing the same as theinputTeleprinter signals or dial pulses inaccordance with Recommendation U.2Call connected Continuous Z polarity
17、 onthe backward path (2 sminimum, possibly fol-lowed by teleprintersignals)Continuous Z polarity(102 bits of Z polarityminimum, possibly fol-lowed by teleprinterignals)Continuous Z polarity (1.997 sminimum, possibly followed byteleprinter signals)Service signal(busy impulse)165-260 ms of Z polarityo
18、n the backward path fol-lowed by A polarity for1500 ms ( 30%) con-tinuously repeated (theA polarity period may bepreceded by teleprintersignals, in which case thetolerance of the A polarityis reduced to 20%)8-14 bits of Z polarity fol-lowed by 53-100 bits ofA polarity continuouslyrepeated or 8-14 bi
19、ts ofZ polarity followed byteleprinter signals followedby 61-92 bits of A polaritycontinuously repeated156-275 ms of Z polarity followed byA polarity of minimum duration1037 ms (the A polarity period may bepreceded by teleprinter signals)Clear andclear-confirmationAs for type A As for type A As for
20、type AAutomatic retest As for type A As for type A As for type AFor notes, see Table 3/U.25.4 Fascicle VII.2 - Rec. U.25TABLE 3/U.25Type C signallingSignallingconditionSignal received from telex(Recommendation U.11)Signal on aggregate path(Note 1)Signal transmittedto telexFree line Continuous A pola
21、rity onboth signalling pathsContinuous A polarity Continuous A polarityCall or automaticretestInversion to Z polarityon forward path for150-300 ms followed byteleprinter signalsInversion to Z plarity for7-16 bits followed byteleprinter signalsInversion to Z polarity (within 50 msof inversion in colu
22、mn 2) for 140-314ms followed by teleprinter signals(Note 2)Transit proceed toselectZ polarity for not less than450 ms folllowed by codecombination No. 22(nominally 40 ms pulse ofA polarity)Not less than 22 bits ofZ polarity followed by2 bits of A polarityNot less than 430 ms of Z polarityfollowed by
23、 40 ms of a polarityReception confirma-tion or equipmentcongestionInversion to Z polarity onbackward path for 450 ms( 10%) followed byteleprinter signals or clear-ing signalInversion to Z polarity for20-26 bits followed byteleprinter signals or con-tinuous A polarityInversion to Z polarity for 391-5
24、10 msfollowed by teleprinter signals or con-tinuous A polarityClear andclear-confirmationAs for type A As for type A As for type ANotes concerning Tables 1/U.25 to 3/U.251. Actual polarity of each channel on the aggregate path will conform to 5.5.1.1 (alternative A) or 5.6.3 (alternative B) ofRecomm
25、endation R.101.2. The time delay of signals through the multiplex equipment shall not exceed 50 ms.3. Pulses of Z or A polarity less than 10 ms shall be rejected by the multiplex equipment.4. The tolerances shown for the Signal transmitted to telex shall not be exceeded when more than one pair of te
26、rminals areconnected in tandem.5. It is accepted that the Signal transmitted to telex may deviate from the tolerances given in the tables when the Signal receivedfrom telex conforms to Recommendation U.24 but not to Recommendation U.1 or U.11. In this event the Signal transmitted to telexshall not exceed the tolerances given in Recommendation U.24.
