| Number | Date | Country | Kind |
|---|---|---|---|
| 2-338628 | Nov 1990 | JPX | |
| 2-340933 | Nov 1990 | JPX |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3766687 | Henson | Oct 1973 | |
| 4150784 | Moorman et al. | Apr 1979 | |
| 4454599 | Tsuchiya | Jun 1984 | |
| 4675858 | d'Alayer de Costemore d'Arc | Jun 1987 | |
| 4803349 | Sugimoto et al. | Feb 1989 | |
| 4931622 | Ohtsuki et al. | Jun 1990 | |
| 5086422 | Hagiya et al. | Feb 1992 | |
| 5146070 | Toma | Sep 1992 | |
| 5179504 | Kitahara | Jan 1993 |
| Number | Date | Country |
|---|---|---|
| 56-105171 | Aug 1981 | JPX |
| 57-29958 | Feb 1982 | JPX |
| 60-247881 | Dec 1985 | JPX |
| 62-164687 | Oct 1987 | JPX |
| 64-72353 | Mar 1989 | JPX |
| Entry |
|---|
| IBM Technical Disclosure Bulletin, Lewis et al., Unidirectional Gate for Card Readers, Jan. 1972, vol. 14, No. 8. |