1、CEPT T/CS*46-02*E = 2326434 0004825 II 0 TCS46-02 Page 1 E Recommendation T/CS 46-02 (Innsbruck 1981, revised at Nice 1985) MULTIFREQUENCY SIGNALLING SYSTEM TO BE USED FOR PUSH-BUTTON TELEPHONES Recommendation proposed by Working Group T/WG 1 1 “Switching and Signalling” (CS) Text of the Recommendat
2、ion adopted by the “Telecommunications” Commission: “The European Conference of Postal and Telecommunications Administrations, considering - that access to the services of the telephone network will be provided by telephone sets equipped with 12 or - that the use of these telephone sets and their si
3、gnalling technique for a simple type of end-to-end data transmission - that the existing CCITT Recommendations on the subject do not yet assure the required standardisation; - that the Administrations are in favour of harmonising telecommunications equipment and systems which could lead to a reducti
4、on in development and manufacturing cost for those industries that provide equipment for several countries, 16 push-buttons as recommended in CCITT Recommendation Q. 1 1 11 for multifrequency signalling; in the international as well as in national networks requires standardisation of the technique t
5、o be used; O recommends the use by the member Administrations of the multifrequency signalling system for push-button telephones (including those of private automatic branch exchanges), conforming with the specifications set out hereafter.” Edition of May 15, 1986 CEPT T/CS*4b-O2*E W 2326434 0004826
6、 3 = O 1. 1.1. 1.2. 1.2.1. 1.2.2. TICS 46-02 E Page 3 BASIC MULTIFREQUENCY PUSH-BUTTON (MFPB) SIGNALLING SYSTEM SIGNALLING SYSTEM PRINCIPLES AND CODING General This section deals with the general characteristics of the signalling system and conforms to CCITT Recommendation Q.23 2. Signal frequencies
7、 and codes Signal frequencies The signal frequencies shall be selected from two separate groups within the speech band (300-3,400 Hz), a low group and a high group, each group providing four signalling frequencies. These frequencies shall be : - low group frequencies: 697, 770, 852 and 941 Hz; - hig
8、h group frequencies: 1,209, 1,336, 1,477 and 1,633 Hz. Signal format Each signal shall consist of two and only two of the signalling frequencies; one frequency from each of the low and high groups. Both frequencies shall be applied simultaneously in parallel across the line. Signal code The 16 discr
9、ete signals shall be allocated as shown in Table 1 (T/CS 46-02) below. 1.2.3. High group frequencies Hr I i209 I 1336 I IL77 I 1633 I I I I Table 1 (T/CS 46-02). Table 1 (T/CS 46-02) gives the full allocation of signal codes. The system may be utilized with only 10 discrete signals, in which case th
10、e signals designated Sc, +I, A, B, C and D will not be used; or with 12 discrete signals, in which case the signals A, B, C and D will not be used. Nute: The presentation in Table 1 (T/CS 46-02) corresponds to the actual lay-out of the push-buttons on the terminal equipment. The arrangements and des
11、ignations of buttons are further specified in Recommendation T/CS 34-01 3. Edition of May 15, 1986 I CEPT T/CS*4b-O2*E 232b414 0004627 5 TICS 46-02 E Page 4 2. 2.1. 2.2. 2.3. 2.3.1. 2.3.2. 2.3.3. 2.3.3.1. 2.3.3.2. 2.3.4. 2.3.5. PUSH-BUTTON SENDER Area of application and general This Section deals wi
12、th the multifrequency sender which is used in push-button telephones. The sender has basically been specified for signalling to the exchange. However, regard has also been taken of the possible use of push-button telephones for end-to-end data transmission when manual operation applies. The requirem
13、ents stated in this section apply to an unregulated generator, i.e. a generator in which the output levels are not controlled by the line current. Operational conditions The sender is expected to operate under varying environmental conditions. (a) A general purpose sender should operate in temperatu
14、re controlled locations and partly temperature controlled locations, i.e. in normal living and working areas as well as entrances, staircases of buildings, factories and industrial plants, etc. The relevant climate conditions are described in Recommenda- tion T/TR 02-06 4. The sender must meet the r
15、equirements within these conditions. (b) A wide temperature range sender should operate in open air as well as sites with heat trap, i.e. telephone booths and similar installations. The relevant climatic conditions are described in Recommen- dation T/TR 02-06, Figure 3 4. The wide temperature range
16、sender must meet the requirements within these conditions. Signal output requirements Frequency tolerance The output frequencies shall be maintained within f 1.5% of their nominal values. This tolerance shall also include the effect of different line impedances offered to the sender. Sending level T
17、he sending levels with a load resistance of 600 ohms shall be for: option 1 - the high frequency group: - 9 dBm +2 dB - the low frequency group: - 11 dBm f 2 dB; option 2 - the high frequency group: - 6 dBm f2 dB - the low frequency group: - 8 dBm +2 dB; with a restriction that the level of the high
18、er frequency component of the compound signal shall be 2 above the level of the lower frequency component. Unwanted frequency components When a signal is output: (a) the total power level of all unwanted frequency components shall be at least 20 dB below the level of the low group frequency componen
19、t of the signal; (b) the level of any individual unwanted frequency component shall not exceed the following limits: - in the frequency band 300-4,300 Hz: -33 dBm; - in the frequency band 4,300-28,000 Hz: -37 dBm at 4,300 Hz, then falling at 12 bB/octave until - in the frequency band 28-70 kHz: -70
20、dBm; - in the frequency band 70-200 kHz: -80 dBm; - in the frequency band above 200 kHz: -70 dBm. 1 dB 28 kHz; When no signal is output, the level of any single frequency emitted from the sender to line shall not exceed -80 dBm. Risetime The level of each of the two frequency components of the multi
21、frequency signal shall be be within 1 dB of the final value within 7 ms from the time that any button is operated. Signal timing When a button is depressed, the signal is output to line. It continues until the button is released. If the signal output is automatically timed, the duration of the signa
22、l shall be 70 In this case. the interdieital Dause shall have a minimum value of 65 ms. 5 ms excluding risetime. O Edition of May 15, 1986 CEPT T/CS*46-02*E m 2326414 0004828 7 TICS 46-02 E Page 5 2.4. 2.4.1. 2.4.2. 2.4.3. 2.4.4. 2.4.5. 2.4.6. Note I. Frequency tolerance The tolerance specified in C
23、CITT Recommendation Q.23 2 is 1.8%. However, it was considered that 1.5% could be achieved in practice without any difficulty for the operating conditions specified in Section 2.2. Note 2. Sending level The lower sending levcls are based on the application of CCITT Recommendation Q.15 5 to the use o
24、f push-button telephones for end-to-end data transmission. Assumptions were made for average power losses and activity factors. The pre-emphasis of 2 dB is a compromise between different national requirements. A tolerance of 1 dB was specified because it can be assumed that the drift in the power le
25、vels of the two single frequency components will be correlated. Note 3. Unwanted frequency components In 9; 2.3.3.1. the requirement (a) is related to the performance of the multifrequency signalling system itself. The requirement (b) is to avoid interference to this and other inband signalling syst
26、ems and other channels in multiplex systems. The specification in 9; 2.3.3.2. assures that none of the frequencies is audible during the conversation condition. Note 4. Risetime While a button is moving from the undepressed to the depressed position, the direct current and alternating current charac
27、teristics of the telephone set are changed, which will cause transients. The transients and the characteristics of the two-frequency signal limit the accuracy with which the risetime can be measured. Further, the time at which the button is operated may be difficult to identify. A firmer requirement
28、 than 7 ms could therefore hardly be verified in practice. The amplitude of the transients depends upon the characteristics of the sender, the local line and the exchange feeding bridge. Although a limitation of the transients is necessary, it has not yet been possible to specify maximum values. Two
29、 factors must be taken into account when specifiying the amplitude and duration of transients: (a) (b) for signalling to the exchange the influence of transients on the receiver performance must be limited; for the purpose of data transmission, Administrations must ensure that in practice (Le. : whe
30、n the telephone, sender, local line and feeding bridge are associated) the amplitude and duration of transients at the output of the exchange feeding bridge does not significantly increase the level of the mean power transmitted to the national network. Note 5. Signal timing Provision is made here f
31、or the timing of signais from the sender to be achieved in either of two ways. Either the signal duration is controlled solely by the length of time the keypad button is deprcsscd, or the sender itself may exert control on thc signal duration in the manner specified. Electrical characteristics Imped
32、ance The return loss of the sender against a pure resistance of 600 ohms shall be at least 14 dB in the frequency band 300-3,400 Hz. Speech suppression When a button is depressed the sending efficiency of the telephone set (from microphone to line) shall be decreased by at least 60 dB. Impedance unb
33、alance to earth The impedance unbalance to earth measured in accordance with the principle of measurement in Recom- mendation 4.45 6 shall be not worse than or equal to: - in the frequency band 40- 300 Hz: 40 dB; - in the frequency band 300- 600 Hz: 50 dB; - in the frequency band 600-3,400 Hz: 55 dB
34、. During the measurement the telephone set shall be placed on a metallic surface which is connected to earth potential. Direct current condition The sender shall be powered by the line current feed. The sender shall function correctly with either normal or reversed current feed. O ver voltage protec
35、tion The sender shall be adequately protected, in accordance with national requirements, against overvoltage, e.g. lightning, with buttons either operated or non-operated. Dial tone The sender shall operate correctly in the presence of dial tone. Note 1. impedance The return loss is specified agains
36、t a pure resistance of 600 ohms as this is in accordance with international practice and maintains a constant reference impedance throughout the specification. However, it is recognised that higher impedances are more appropriate for a number of national networks. Edition of May 15, 1986 CEPT T/CS*Y
37、b-OZ*E M 2326434 0004829 9 = TICS 46-02 E Page 6 Note 2. Direct current conditions The current feeding systems used by Administrations can differ significantly to the extent that it is not possible to specify requirements other than those stated in Q 2.4.4. However, in order to facilitate the realis
38、ation of a common design of sender to meet the requirements of different direct current feeding systems to be used with push-button telephones, the following information is provided. i) Minimum and maximum conditions of the feeding systems in different countries are given in Table 2 (T/CS 46-02) bel
39、ow. The column minimum current relates to the current needed to hold the connection. ii) The minimum and maximum conditions for each system can be represented by straight lines in a U/I diagram, Figure 1 (T/CS 46-02): maximum condition U = U, - I . R,!“ minimum condition U = UmiO-I . Rmx Country Bel
40、gium Denmark Finland 1 Finland 2 France 1 France 2 FR Germany Italy Netherlands Norway Spain 1 Spain 2 Sweden 1 Sweden 2 Switzerland 1 Switzerland 2 United Kingdom Battery voltage (VI min. 44 44 44 56 45 90 57 44 42 44 44 44 31 42 44 56 45 max. 52 56 53 66 53 106 64 52 56 52 52 56 45 56 54 66 52 Tot
41、al resistance of feeding bridge and line min. 400 450 700 900 300 1,400 1,260 720 640 500 300 500 1,000 1,600 700 1,000 3 60 max. 1,600 2,480 2,500 2,700 1,820 2,800 3,240” 3,O 1 O 2,140 2,000 2,340 1,856 2,200 3,400 1,700 2,000 1,450 Minimum current (mA) 20 15.3 15 18 12 12 17 1 22 16 17 10 15 11 9
42、.5 21 22.5 25 Table 2 (T/CS 46-02). I This includes the resistance of the telephone. The area between these lines represents all possible feeding conditions for the sender. The part of this area with currents smaller than the minimum current should not be entered by the U/i curve of the sender. For
43、the systems in Table 2 (T/CS 46-02), the lowest points of this forbidden area have been calculated, and are shown in Table 3 (T/CS 46-02). iii) A curve through the lowest points as shown in Figure 1 (T/CS 46-02) represents the lower boundary of the forbidden area B, for a sender which is suitable fo
44、r all systems in Table 2 (T/CS 46-02). The other boundaries for area B are a vertical line starting in the point with the highest minimum current (25 mA) and lines representing the extremes in minimum feeding conditions (S, and S2). iv) For the systems mentioned in Table 2 (T/CS 46-02); the upper li
45、mits are determined by the extremes in maximum feeding conditions. v) Area C represents conditions which will not occur during normal operation. vi) For a sender suitable for all systems in Table 2 (T/CS 46-02), the meaning of the areas is as follows. - For all conditions represented by the part of
46、the U/I curve in area A, all requirements should be fulfilled. This value also ensures the proper functioning of the meter at the subscribers premises. Edition of May 15, 1986 CEPT T/CS*46-02*E H 2326434 0004830 5 TICS 46-02 E Page 7 Edition of May IS, 1986 CEPT T/CS*Yb-OZ*E D 232b414 0004833 7 D 3.
47、 3.1. 3.2. 3.3. 3.3.1. Country I Current (mA) Belgium Denmark Finland 1 Finland 2 France 1 France 2 FR Germany Italy Netherlands Norway Spain 1 Spain 2 Sweden i Sweden 2 Switzerland 1 Switzerland 2 United Kingdom 20 15.3 15 18 12 12 17 12 16 17 10 15 11 9.5 21 22.5 25 Voltage (volts) 12 6.12 6.5 7.4
48、 23 56 9.2 7.88 7.76 10.0 10.6 16.16 6.8 9.7 8.3 8.76 11 Table 3 (T/CS 46-02). - The U/I curve should not enter area B. In area C there are no requirements. Note 3. Overvoltage protection The overvoltage protection provided should also take care of the effects of the ringing voltage which might occu
49、r with buttons either undepressed or depressed. Note 4. Control tone If a control tone is required by Administrations when a button is depressed then it is necessary to specify a requirement for the sender such that the tone at the telephone receiver is at an acceptable level, e.g. about 65 to 85 dB relative to 20 pPa measured by a CCITT recommended artificial ear. THE RECEIVER FOR ANALOGUE EXCHANGES Area of application This Section deals with the receiver or receiver function for use in local exchanges and in private automatic branch exchanges. The receiver shall respo
