system: You are a contract-analysis assistant performing a span-extraction task. You are given an excerpt from a commercial contract and the name of a clause type to locate within it.

Return the exact text of the requested clause, copied verbatim from the excerpt — identical wording and punctuation, with no paraphrasing, summarising, explanation, or added commentary.

The excerpt is one window of a much longer contract and often will not contain the requested clause. If the requested clause does not appear in this excerpt, respond with exactly: Not found.

Output only the extracted clause text, or the exact string `Not found.` — nothing else.

user: Contract excerpt:
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or Congestion 6 Number Unobtainable 7 SIT 8 Dial Tone 9 Unknown Tone ------------------------------------------- Table A-6: Tone Detection Precedence Table A-6 shows the precedence of typical tones that the UTD module detects. Modem signals have the highest precedence, and Unknown tones have the lowest. Therefore, the frequency range of unknown tones can safely overlap the other tone ranges without causing tones to be misclassified. If the range for Unknown tones is allowed to be the maximum range allowed by the detector, any detected tone that is unclassified would be designated as Unknown. A.5.3.1.5 North American Call Progress Signal Detection Functional Requirements: The tables below specify the frequencies, power levels, and cadence of the Bellcore and EIA-464A call progress tones. - -------------------------------------------------------------------------------- Frequency (Hz) Power Level (dBm) - -------------------------------------------------------------------------------- Name 350 440 480 620 Per Frequency Combined - -------------------------------------------------------------------------------- Audible Ring X X -22.5 +/- 1.5 - -------------------------------------------------------------------------------- Busy X X -27 +/- 1.5 - -------------------------------------------------------------------------------- Dial Tone X X -17.5 to -15 -13 to -14.5 - -------------------------------------------------------------------------------- Intercept X X -20 +/- 1.5 - -------------------------------------------------------------------------------- Reorder X X -27 +/- 1.5 - -------------------------------------------------------------------------------- Table A-7: Call Progress Tone Frequency and Power Requirements Software License D2 Technologies, Inc. and Maintenance Agreement August 4, 1997 CONFIDENTIAL 33 - ------------------------------------------------------------------------------- Audible ring (ring- repetition of the tone on for 0.8 to 2.2 seconds, and back) off for 2.7 to 4.4 seconds - ------------------------------------------------------------------------------- Busy repetition of the tone on for 0.5+/-0.05 seconds, and off for 0.5 +/-0.05 seconds - ------------------------------------------------------------------------------- Dial steady uninterrupted - ------------------------------------------------------------------------------- Intercept repetition of an alternating sequence, of the two frequencies each being on for 0.16 to 0.30 seconds with a total cycle time of 0.5 +/-0.05 seconds - ------------------------------------------------------------------------------- Reorder (fast busy) repetition of the tone on for 0.25+/-0.025 seconds, and off for 0.25+/-0.025 seconds - ------------------------------------------------------------------------------- Table A-8: Call Progress Tone Cadence Performance Requirements: 1. Frequency Deviation: Even though the generator is required to meet a frequency tolerance per tone of +/-0.5%, the detector needs to allow for a wider frequency tolerance due to variations in generators and line distortions. The CP detector detects all tones whose component frequencies deviate less than 1% from nominal. 2. Twist: The CP detector detects all tones whose twist is less than +/-4 dB. 3. Dynamic Range: The CP detector exhibits a minimum dynamic range of 25 dB. 4. Cadence: The CP detector must detect call progress tones whose cadence is within +/-10%. 5. Talkoff: The CP detector makes no false detections in 12 hours of testing with voice at -15 to -18 dBm ASL. A.5.3.1.6 FAX CNG Tone Detection The standard connection protocol for automatic connection of a FAX modem requires that the calling FAX modem generate a calling tone (CNG). Hence for incoming calls, the EVP software has to detect a CNG signal. When CNG is detected, EVP alerts the Core Processor to redirect the call to a FAX machine or a FAX modem embedded within the call processing system. Software License D2 Technologies, Inc. and Maintenance Agreement August 4, 1997 CONFIDENTIAL 34 Functional Requirements: Detect the presence of the FAX calling tone (CNG). A CNG signal is defined as follows. INSERT GRAPH Figure A-5: Fax calling tone (CNG) a) The CNG tone is within 38 Hz of nominal frequency. b) The timing tolerance of a CNG tone is +/-15%. c) The power of a CNG tone is between 0 and -43 dBm. Performance Requirements: 1. The detector does not miss any CNG signals on a prerecorded tape containing 50 CNG tone samples collected from S different FAX machines. 2. The detector does not miss any CNG signals from the same FAX machines connected to a local CO with a noise level of less than -45 dBm. 3. The detector misses less than 0.5% of CNG signals (generated at -10 dBm) when compressed voice is output at a level of-15 dBm or less (average over 3 seconds) into a network whose ERL is greater than 15 dB. 4. The detector does not falsely detect more than 1 CNG tone per 5 hours of voice (based on Bellcore recorded talk radio voice tapes.) A.5.3.1.7 Modem Tone Specification All answering modems that conform to the ITU V.25 answering sequence present a 2100 Hz tone 1.8 to 2.5 seconds after answering the telephone line. Figure A-6 and Figure A-7 show the timing of the answering tone (ANS). In Figure A-6, the 2100 Hz Software License D2 Technologies, Inc. and Maintenance Agreement August 4, 1997 CONFIDENTIAL 35 tone reverses phase every [tau] intervals.
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Extract the exact clause related to "Third Party Beneficiary" from the excerpt above.

assistant: Not found.