GB/T 15279-2002The specifications of automatic telephone set (English PDF)

4.2 Call transfer characteristic

4.2.1 Loudness rating Connect the telephone set to analog telephone network test system. Its sending and receiving loudness ratings and side tone masking rating shall meet the requirements of Table 1.

4.2.3 Receiving frequency response Under the condition of 0km user line, the typical curve (the broken line shown in Figure 2) and range of permissible deviation (the solid line shown in Figure 2) of receiving frequency response are shown in Figure 2.

4.2.5 Nonlinear distortion

4.2.6 Maximum sound level in case of switching on and off of telephone set The maximum sound level in case of switching on and off of telephone set shall not be greater than 125dB(A).

4.2.7 Noise characteristic

4.2.8 The telephone set shall not have any singing phenomenon in normal use.

4.2.9 The DC resistance of the telephone set in off-hook state shall not be greater than 350Omega.

4.3.2 Characteristic of dual-tone multi-frequency signal

4.3.2.6 Power level of unwanted signal When the telephone set is dialing, the total power level of the unwanted frequency component in output signal shall at least be 20dB lower than the power level of the low frequency component in dual-tone multi-frequency signal.

4.4 Characteristic of telephone ringer

4.4.1 Ringing power sensitivity The ringing power sensitivity of the telephone set shall not be greater than 100mVA.

4.6 Characteristics of telephone cord and handset cord

4.6.1 If socket is used for the terminals of telephone cord and handset cord, the plug used shall meet the requirements of YD/T 577.

4.7 Key "R" The telephone sets provided with key "R" shall be marked with word "R" clearly. After key "R" has been pressed, the interruption time of talking circuit shall be between 90ms-130ms. The off resistance in case key "R" functions shall not be less than 100kOmega.

4.10 Environmental suitability of telephone set

4.11 Lightning resistance of telephone set The lightning resistance of telephone set shall meet the requirements of YD/T 993-1998. After going through the lightning resistance test specified in 5.20, the various functions shall remain normal.

4.12 Electromagnetic compatibility of telephone set The electromagnetic compatibility of telephone set shall meet the requirements of YD/T 968.

4.13 Functional requirements for telephone set

4.13.1 The functions specified in the operation instruction of telephone set shall be normal and meet he requirements of relevant specifications.

4.14 Reliability requirements for telephone set The mean time between failures (MTBF) of telephone set shall not be shorter than 5 000h.

5.1 Test conditions

5.1.1 Test under normal conditions Unless otherwise specified, all the tests shall be carried out under the following normal conditions.

5.1.2 Feed bridge circuit used for testing purposes The feed bridge circuit is shown in Figure

5.In this figure, E is (48±1)V, C is (4±0.4)µF, L is composed of two groups of symmetrical coils.

5.1.3 Artificial user line network The artificial user line network per kilometer used for testing purposes shall be fabricated according to Figure 6 to simulate phi = 0.5mm core wire paper insulated cable.

5.1.5 Artificial mouth The artificial mouth shall have the following characteristics.

5.2 Testing of loudness rating

5.2.1 Test instruments and equipment The objective measuring apparatus used for the testing of loudness rating shall meet the requirements of ITU-T P.64 and ITU-T P.79.

5.2.4 Testing of side tone masking rating (STMR)

5.2.4.1 Measurement of sound pressure of mouth reference point (with respect to 1Pa/V) Carry out the measurement of sound pressure of mouth reference point (Pm) according to 5.2.2.1.The test frequency range shall be extended to 100Hz-8 000Hz.

5.5.1.1 Connect the test circuit according to Figure

12.The sinusoidal signal generator emits sinusoidal signals of difference frequencies. The free field sound pressure of mouth reference point (Pm) is the same as in the measurement of sending sensitivity, i.e., -4.7dBPa.

5.5.2.1 Connect the test circuit according to Figure

13.The sinusoidal signal generator emits sinusoidal signals of difference frequencies. The level is the same as in the measurement of receiving sensitivity. The internal resistance of signal source is 600Omega.

5.6 Measurement of noise characteristic of telephone set

5.6.1 Measurement of sending noise Connect a 600Omega resistor to the output end of the telephone set and carry out the measurement according to Figure

14.Set the noise meter to input high impedance and calibrate it in dBV. The weighting coefficient of the noise meter shall meet the regulations of Table 1 of ITU-T suggestion 0.41.Under the condition that there's no excitation sound pressure and the ambient noise is not greater than 40dB(A), measure the mean values of three cycles longer than 1s and take the minimum value.

5.7 Measurement of the maximum sound level in case of switching on and off of telephone set

5.7.1 Connect the circuit according to Figure 16. Figure

16 Measurement of the maximum sound level in case of switching on and off of telephone set

5.7.2 The feed bridge shall meet the regulations of 5.1.2.

5.8.1 Connect the test circuit according to Figure

17.In this figure, the telephone sets shall be of the same model and in off-hook power supply state, the supported telephone handset shall be put on the side.

6.1 Marking

6.1.1 The telephone sets that have passed the tests shall be marked with the model, trademark, network access mark and date of production of the telephone set.

6.1.2 The contents marked on the packing box of each telephone set includes the model, name, trademark, name of manufacturing factory or company, color and executed standard of the telephone set.

6.1.3 The contents marked on the packing case of multiple telephone sets include.

6.2 Packing

6.2.1 The telephone sets shall be provided with general shock-proof and damp-proof packing.