Frequencies 1. Detect the presence of all 16 DTMF digits that are produced by different phones on the market under a broad range of network conditions. 2. DTMF digit information is provided as soon as the minimum duration is met. This information is called leading edge detection. This allows the earliest possible response to the digit, such as stopping voice output. 3. The trailing edge of a DTMF digit must be detected. This allows the system to delay any response (such as playing out voice) to the digit until the user has released the DTMF key. The criteria selected for trailing edge detection will debounce DTMF digits. 4. The DSP reports leading and trailing edge in the 8 ms block that they are detected. DTMF events are not buffered. A.3.2 Performance requirements: Table A-2 consists of performance requirements taken from EIA-464A and Bellcore TR-TSY-000181. Also shown is D2's DTMF performance requirements, which is a superset of the EIA and Bellcore requirements. Software License D2 Technologies, Inc. and Maintenance Agreement August 4, 1997 CONFIDENTIAL 23 - -------------------------------------------------------------------------------------------------------------------- Requirement - -------------------------------------------------------------------------------------------------------------------- Characteristic Bellcore EIA/TIA-464A D2 - -------------------------------------------------------------------------------------------------------------------- Frequency Deviation +/-1.5% must accept; +/-1.5% must accept; Configurable choice of +/-3.5% must reject +/-3.5% must reject four sets of must accept/must reject: +/-2.0% accept to +/-3.0% reject; +/-2.5% accept to +/-3.5% reject; +/-3.0% accept to +/-4.0% reject; +/-3.5% accept to +/-4.5% reject. - -------------------------------------------------------------------------------------------------------------------- Minimum Tone 40 ms must accept; 23 40 ms must accept Configurable from 24 Duration ms must reject to 80 ms - -------------------------------------------------------------------------------------------------------------------- Minimum Interdigital 40 ms 40 ms Configurable from 24 Interval to 80 ms - -------------------------------------------------------------------------------------------------------------------- Minimum Cycle Time 93 ms 93 ms Configurable from 48 to 160 ms - -------------------------------------------------------------------------------------------------------------------- Accept Levels 0 to -36 dBm must 0 to -25 dBm must 0 dBm to configurable accept,