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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-55 dBm must accept minimum (-25 to -45 reject dBm range) - -------------------------------------------------------------------------------------------------------------------- Twist (ratio of high -8 to +4 dB -8 to +4 dB Separately group power to low) configurable positive and negative twists: +/- 4, 6, 8, 10, and 12 dB - -------------------------------------------------------------------------------------------------------------------- Bellcore talkoff tape Fewer than 670 total - Fewer than 20 talkoffs talkoffs; fewer than (with default 330 talkoffs of digits 0- configuration of 2.5% 9; fewer than 170 to 3.5% frequency talkoffs of signals * deviation; 40 msec min and #. tone duration; +/- 8 dB twists; -45 dBm min accept level) - -------------------------------------------------------------------------------------------------------------------- Mitel talkoff tape - - 0 talkoffs (with default configuration) - -------------------------------------------------------------------------------------------------------------------- SNR 23 dB 15 dB 15 dB - -------------------------------------------------------------------------------------------------------------------- Impulse Noise Fewer than 14 missed Fewer than 10 errors Pass both Bellcore and or split digits in in 10,000 tones for EIA EIA/TIA-464A Bellcore Impulse Noise test #1; fewer than 500 impulse noise Tape No. 201 errors in 10,000 tones requirements for test #2 - -------------------------------------------------------------------------------------------------------------------- Software License D2 Technologies, Inc. and Maintenance Agreement August 4, 1997 CONFIDENTIAL 24 - ------------------------------------------------------------------------------------------------------------------- Echo 16 dB Signal-to-Echo 10 dB Signal-to-Echo Pass both Bellcore and ratio at 20 ms; 24 dB at ratio at 20 ms EIA/TIA-464A echo 45 ms requirements - ------------------------------------------------------------------------------------------------------------------- Dial Tone DTMF Detection in the DTMF Detection in the Pass both Bellcore and presence of dial tone presence of dial tone EIA/TIA-464A at -15 dBm per dial at -16 dBm per dial requirements for tone frequency tone frequency detection of DTMF digits in the presence of dial tone - ------------------------------------------------------------------------------------------------------------------- TABLE A-2: DTMF Performance Requirements Other performance requirements: 1. A leading edge of DTMF digit is signaled during the block in which the minimum duration is met, and the trailing edge is signaled during the block in which the minimum debounce interval is met. 2. Talk-down: DTMF detection must work reliably in the presence of echo (for the maximum allowable output voice level) and with varying levels of DTMF signals (due to network loss). D2's DTMF detector combined with the echo must meet the performance requirements of Figure A-I in the presence echo generated by playing pause-removed voice (male and female) at - 18 dBm ASL (averaged over 3 seconds) over a telephone circuit with 15 dB echo return loss (ERL). INSERT GRAPH Figure A-1: DTMF Talk-down Acceptance Curve 3. Debounce test: Long tones (generated by "hard" key presses) must not be detected as multiple tones in the presence of echo interference or line noise. Combined with the echo canceller, the DTMF detector is required to reliably "debounce" all DTMF digits above -18 dBm in the presence of voice levels below -15 dBm (ASL) and a telephone circuit with echo return loss (ERL) of 15 dB. Software License D2 Technologies, Inc. and Maintenance Agreement August 4, 1997 CONFIDENTIAL 25 4. Double-talk talk-off: Many voice processing hardware or semiconductor manufacturers significantly degrade the "talk-off' performance of their detector in the presence of voice echo or sidetone to achieve a high level of talk-down performance. This strategy is acceptable in a pure digit-in-voice-out scenario, but for voice conferencing or voice recognition applications, voice could be present in the both the transmit and receive path. In such cases, the DTMF detector must be very robust against "talk-off" in double-talk situations. The talk-off requirements for D2's DTMF detector under double-talk is fewer than 66 talkoffs for the Bellcore talk-off tape. A.4 Tone Generation The tone generation module can be programmed to generate any single, dual or amplitude modulated tone required to meet international telecommunications specifications. This functionality is provided by the GENF module, which produces the sum or product of two independently generated sine waves as its output. Each sine wave can be individually parameterized. A.4.l Functional requirements: The GENF module is designed to generate a wide range of DTMF, Call Progress Signals, MF Rl/R2, and miscellaneous tones. In order to meet or exceed international telecommunication specifications, GENF must meet or exceed the following functional requirements. 1. Independent arguments shall be supplied for each frequency for dual tones that GENF generates. Single tones are generated by specifying that one of the dual tone's frequencies is 0 Hz. 2. Independent arguments shall be supplied for the carrier and modulation frequencies for amplitude modulated tones that GENF generates. 3. Arguments shall be supplied that allow the frequency of a tone to be set in the range of 0 to 4000 Hz in 1 Hz units. 4. Arguments shall be supplied that allow the
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Extract the exact clause related to "Parties" from the excerpt above.

assistant: D2