Number | Name | Date | Kind |
---|---|---|---|
4885763 | O'Brien et al. | Dec 1989 | A |
5172406 | Locke | Dec 1992 | A |
5408529 | Greaves | Apr 1995 | A |
5519764 | Pierce et al. | May 1996 | A |
5528663 | Locke et al. | Jun 1996 | A |
5588053 | Xie | Dec 1996 | A |
Entry |
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DTMF Digital Detection and Removal, D2 Technologies, Inc., Web page, Jan. 29, 1998. |
GAO STMF Detector/Generator/Remover, GAO Research & Consulting Ltd., Web page, Jan. 29, 1998. |