IEEE 269-1992 pdf free.IEEE Standard Methods for Measuring Transmission Performance of Analog and Digital Telephone Sets.
IEEE 269  circuit for receive is shown in Fig 12b or Fig13b.The measurement procedure should be as in 6.4.2.
Sidetone Frequency Response. The test circuit for sidetone is shown in Fig 12c or Fig13c.The measurement procedure should be as in 6.5.2.The reference codec is not used in themeasurement but may remain in the test circuit.
Overall Frequency Response.The overall response should be measured using two tele-phone sets back-to-back,connected through the interfaces without the ideal codec.The testcircuit for overall is shown in Fig 12d or Fig 13d.The measurement procedure should be as in6.6.2.Signal-to-Distortion Ratio. The handset should be isolated from sound input ormechanical disturbance that may introduce significant error.
Transmit.The transmit signal-to-distortion ratio is the ratio of the signal power of apure tone to the C-message weighted distortion power at the output of the reference codec.Using Fig 12a, transmit a pure tone following the procedures in 6.3.2.The output signal ismeasured according to Section 4.3.2 of IEEE Std 743-1984 [12].The pure tone typically has afrequency between 1004 Hz and 1020 Hz and an input level between 60 dBSPL and105 dBSPL.
Transmit.The transmit characteristics should be measured per 7.3 over the range oftypical input levels. The departure of the output to input from a ratio of 1:1 in decibels is ameasure of nonlinearity.
Receive. The receive characteristics should be measured per 7.4 over the range oftypical input levels. The departure of the output to input from a ratio of 1:1 in decibels is ameasure of nonlinearity. Noise. During the measurement of noise, the transmitter should be isolated from soundinput and mechanical disturbances.
Transmit. With the telephone set connected to the reference codec and in the activestate with no acoustic input, measure the output of the reference codec using a C-messageweighted meter. (See 5.15.1.)
Receive. With the telephone set connected to the reference codec, which is transmit-ting one of the quiet codes, and the handset ear-cap sealed to the artificial ear， measure theoutput of the artificial ear using the A-weighted meter.(See 5.15.2.)
Acoustic Echo Path Loss.The attenuation from codec analog input to the codec analogoutput is measured as a function of frequency, using either discrete frequencies as recom-mended in 5.20 or by using the continuous spectrum signal of 5.5.See Fig 14.
Sealed.With the handset in the test fixture and the ear-cap sealed to the artificialear, measure the attenuation.IEEE 269 pdf download.