This standard specifies the general requirements for dual tone multi-frequency key dials for telephones. This standard applies to dual tone multi-frequency key dials for automatic telephones (hereinafter referred to as dials). GB/T 9035-1988 Technical requirements for dual tone multi-frequency key dials for telephones GB/T9035-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Technical requirements of
pushbutton dialer with DTMF
This standard specifies general requirements for the pushbutton dialer with DTMF for telephones. This standard applies to the pushbutton dialer with DTMF for automatic telephones (hereinafter referred to as the dialer). Environmental conditions for use:
Temperature: -10~40℃
Relative humidity: 45%~95%
Air pressure: 86~106kPa
1 Keyboard
1.1 Arrangement of keys of rectangular dial:
1.1.1 4×3 array as shown in Figure 1.
4×4 array as shown in Figure 2.
Note: \A", "B", "C", "D\" keys are spare keys and should be represented by capital letters. 1.2 The recommended size of the key center distance of the rectangular dial is 17mm. 3
1.3 The arrangement and spacing of keys of other shapes are specified in the product technical requirements. 1.4 The "*" key and the "#" key are function keys
1.5 When blind keys are set, an identification mark should be added to the "5" key. 1.6 The pressing force of the key should be 1.2±0.6N, and the stroke should not exceed 3.5mm. 1.7 The writing on the key should be clear and eye-catching, and the font proportion should be coordinated. 2 Electrical performance
2.1 Frequency combination, frequency tolerance and level of dual-tone multi-frequency signal: 2.1.1 Frequency combination of dual-tone multi-frequency signal: Approved by the Ministry of Electronics Industry of the People's Republic of China on March 2, 198850
GB 9035-88
Implementation on October 1, 1988
GB 9035-88
High frequency group I, ～. and low frequency group LL. form 16 kinds of dual-tone multi-frequency signals. Frequency combination see Table 1 Table 1
Number or symbol
Low frequency group frequency Hz
High frequency group frequency
2.1.2 The frequency tolerance range of single--frequency in the frequency combination shall not exceed ±1.5% of the nominal value. 2.1.3 Level of dual-tone multi-frequency signal:
High frequency
Low frequency
-7 dBm±3 dB
-9 dBm±3 dB
The level of the high-frequency component in the frequency combination should be 2±1 dB higher than the level of the low-frequency component11
2.2 When sending a number, after the dual-tone multi-frequency signal level reaches 90% of the stable value, the signal duration should be no less than 10ms. The time interval between two adjacent groups of dual-tone multi-frequency signals should be no less than 10ms. 2.3 When sending a number, the total power level of the useless frequency components in the output signal of the dial should be 20 dB lower than the power level of the low-frequency components in the dual-tone multi-frequency signal.
2.4 When not sending a number, the level of each single-frequency signal in the dual-tone multi-frequency signal at the output end of the dial should not exceed -70dBm. 2.5 Under normal atmospheric conditions, the No. 2.6 disk should have no flying or punch-through phenomenon when subjected to a sinusoidal AC voltage of 50Hz and 500V effective value for 1min.
Under normal atmospheric conditions, the insulation resistance of the No. 2.6 disk should be no less than 500M2. 3 Lifespan www.bzxz.net
After each key of the No. 2.6 disk is used 5×105 times, it should meet the requirements of Article 2.1. 4 Basic environmental adaptability
The No. 2.1 disk should meet the requirements of Article 2.1 at a low temperature of 10℃ and a high temperature of 40℃. 4.2 After being stored at -40℃ and 55C and restored under normal atmospheric conditions, the No. 2.1 disk should meet the requirements of Article 2.1. 4.3 After the guide disk is subjected to sweep vibration in the frequency range of 10～55Hz and the displacement amplitude of 0.35mm, there should be no mechanical damage or structural looseness, and it should meet the requirements of Article 2.1.
4.4 After the collision with the peak acceleration value of 100m/s2 and the pulse duration of 16ms, the disk should have no mechanical damage and structural looseness. And it should meet the requirements of Article 2.1.
4.5 When the temperature is 40℃ and the relative humidity is 90%-95%, the insulation resistance should be not less than 50M2, the metal parts should have no rust, and it should meet the requirements of Article 2.1.
Additional instructions:
This standard is under the jurisdiction of the Standardization Research Institute of the Ministry of Electronics Industry. This standard was drafted by Shanghai Telecommunications Equipment Factory and the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications.
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