Number | Date | Country | Kind |
---|---|---|---|
67252 A/80 | Feb 1980 | ITX |
Number | Name | Date | Kind |
---|---|---|---|
3720793 | Hofmann | Mar 1973 | |
3941939 | Holmes et al. | Mar 1976 | |
3978293 | Feiner | Aug 1976 | |
4087646 | Brolin et al. | May 1978 | |
4262172 | Brolin | Apr 1981 |
Number | Date | Country |
---|---|---|
2239128 | Feb 1974 | DEX |
4424535 | Sep 1966 | JPX |
Entry |
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"A New Electronic Ring-Trip Circuit", by Katsumi and Ariizumi, Review of the Electrical Communication Laboratory, vol. 19, Nos. 1-2, Jan.-Feb. 1971, pp. 37-43. |