steady state value for more than 400 musec. INSERT GRAPH Figure A-6: Timing for Answering Modem with Phase Reversal A timing diagram for an answering modem without phase reversal is shown in Figure A- 7. The timing is identical with that of phase reversing tone except for the reversal timing. INSERT GRAPH Figure A-7: Timing for Answering Modem without Phase Reversal Table A-9 contains the nominal frequency, power, and duration requirements for ------------------------------------------------ Minimum Maximum Unit --------------------------------------------------------------------- Frequency 2085 2115 Hz --------------------------------------------------------------------- Duration 2.6 4.0 seconds --------------------------------------------------------------------- Power -18.0 -6.0 dBm0 --------------------------------------------------------------------- generating modem tones as derived from V.25 and G.164. Table A-9: Modem Tone Generation Requirements Performance Requirements: Software License D2 Technologies, Inc. and Maintenance Agreement August 4, 1997 CONFIDENTIAL 36 1. The detector does not miss any modem answer tone on a pre-recorded tape containing 50 modem answer tone samples collected from 5 different data modems. 2. The detector does not miss any modem answer tone signals from the same data modem connected via a local CO with a noise level of less than -45 dBm. 3. The detector does not miss more than 0.5% of modem answer tones (generated at -10 dBm) when compressed voice is played at a level of -15 dBm (ASL) or lower into a network connection with ERL greater than 15 dB. 4. The detector does not falsely detect the presence of a modem answer tone more than once per 5 hours of voice (using Bellcore recorded talk radio voice tapes). 5. There is no talkdown performance requirement. The near end is always silent and does not interfere with far end modem ANS signals. 6. There shall be fewer than 1 talkoff in 5 hours of call classification when the detector is programmed with the recommended parameters. Assuming that each call is resolved