Hello Danny,
 In a message dated 10 Nov 96 you wrote to All :

 DK> Has anybody out there got the frequencies for DTMF tones?

Here's everything you wanted to know about DTMF and more!!

btw are you going to write a program that uses these tones?

From Austel's Technical Standard TS002 (1996)
---------------------------------------------

DTMF Signalling

CE which generates DTMF signals shall comply with the following:

(a) Signalling Frequencies

    (i)  The DTMF signals generated shall consist of pairs of frequencies
         in accordance with ITU-T Rec. Q.23 [14] and shall be allocated
         to the various digits, symbols and characters shown in
         Table 4.

    (ii) The tolerance of each frequency generated shall be less than
         +/- 1.5%.


                                 Table 4

                       DTMF Signalling Frequencies

   Low Group                    High Group Frequencies (Hz)
  Frequencies
     (Hz)           1209         1336        1477         1633

    697              1            2           3            A

    770              4            5           6            B

    852              7            8           9            C

    941              *            0           #            D


Note 1:  The provision of the frequency combinations shown as 'A,B,C,D'
         in Table 4 is not mandatory.

Note 2:  The designations of 'A,B,C,D' should not be confused with the
         alphanumeric allocations detailed in Clause 5.1.8.

(b) Send Levels

    (i)  The power level of any fundamental frequency shall be between
         -5 dBm and -22 dBm for line lengths between 0km and 4.2km
         using 0.40mm conductor cable.

    (ii) For DC line conditions, provided by DC feed resistances between
         400 ohms and 2300 ohms, the pover level difference between any two
         fundamental frequencies shall be 2dB +/- 2dB on a zero line
         length.  The higher frequency tone shall be at the higher level.

(c) Output Rise and Fall Times

    The output rise and fall times of each tone, measured between 10% and
    90% of full amplitude, shall be within 5ms with the CE connected to all
    line lengths between 0km and 4.2 km using 0.40mm cable terminated in
    600 ohms.

(d) Distortion

    The total distortion products (measured as harmonics or intermodulation)
    shall be at least 20dB below the level of the lower power fundamental
    frequency when measured at the line terminals of the CE.

(e) Timing

    The timing for automatically and/or repertory dialled DTMF signalling
    shall be as follows:

    (i)  The minimum duration of the DTMF burst representing each
         digit shall be 50 ms.

    (ii) The minimum interval between the transmission of digits shall
         be 70ms and in no case exceed a maximum period of 3 s unless
         due to a programmed pause.

(f) Line Termination Characteristics

    During DTMF signalling over the frequency range 600Hz to 1660Hz for
    DC line conditions, provided by DC feed resistances between 400 ohms and
    2300 ohms, the source impedance of the CE shall have a return loss
    greater than:

    (a)  10 dB with respect to 600 ohms; and

    (b)  12 dB with respect to the complex impedance as shown in
         Figure 4 which comprises of 220 ohms in series with the parallel
         combination of 820 ohms and 120 nF.

    Note: To facilitate the measurement of this requirement, equipment
          suppliers should provide details of the test configuration for
          the CE.



Josh Marshall                        FidoNet   3:640/201.14
Member TEAM AMIGA                    AmigaNet 41:400/869.14

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