| Number | Name | Date | Kind |
|---|---|---|---|
| 2684996 | Potts | Jul 1954 | |
| 3516062 | Spraker | Jun 1970 | |
| 3657479 | Sweenie et al. | Apr 1972 | |
| 3716835 | Weinberg et al. | Feb 1973 | |
| 3757048 | McAvoy et al. | Sep 1973 | |
| 3865994 | Bender | Feb 1975 | |
| 3870821 | Steury | Mar 1975 |
| Number | Date | Country |
|---|---|---|
| 1,762,551 | May 1970 | DT |
| Entry |
|---|
| Computer Decisions Nov. 1969 p. 72 "Batteries Power Acoustic Terminal". |
| IBM Technical Disclosure Bulletin "Walle. Terminal Keyboard with Acoustic Coupler" M. F. Davis et al. vol. 10 No. 3 Aug. 1967 pp. 188-189. |