Space and time switch for 22 PCM highways
US4809261A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 10, 1987 |
| Grant date | Feb 28, 1989 |
| Priority date | — |
| Expiry date | Jul 10, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q11/06
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A space and time switch receives digitized voice and/or data as twenty-two separate serial bit streams with each voice or data path occupying one time-slot on one bus, resulting in a total of 704 paths entering the switch. The switch originates twenty-two buses and the information in any incoming path can be switched to any outgoing path providing a 704-by-704 switching function. The switch includes six basic functional blocks: input, output, speech RAM, control RAM, controller interface, and state machine. The controller interface receives commands in the form of twenty-four bits appearing as three bytes in three separate operations, stores the bytes until all three are ready, and transfers the command bytes as a combination of address and data bits. The speech RAM stores a complete frame of the data transferred within each time-slot. The control RAM stores commands from the controller interface. The state machine controls operation of the functional blocks and controls readout of the commands from the control RAM, which become addresses for the speech RAM.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.