Monitor/hands-free intercom
US6091329A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 25, 1997 |
| Grant date | Jul 18, 2000 |
| Priority date | — |
| Expiry date | Sep 25, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/40
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A monitor/hands-free intercom system includes a child unit and a parent unit which are each transceivers. The parent unit operates primarily as a receiver, unless and until a talk switch is actuated on the parent unit, enabling the parent unit to transition to a transmitter. The child unit acts primarily as a transmitter unless and until it detects a carrier signal at the appropriate frequency during one of its short sniff periods. If a carrier signal is detected, the child unit extends the sniff period to look for a non-audible hidden tone encoded into the transmission from the parent unit. If the hidden tone is detected, the child unit transitions to a receiver mode and is able to play back the sound waves detected by the parent unit so that the parent can reassure or provide instructions to the child.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.