Mechanism for determining whether channel unit is installed in D4 channel bank slot
US5940374A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 3, 1996 |
| Grant date | Aug 17, 1999 |
| Priority date | — |
| Expiry date | Sep 3, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04J3/14
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A D4 channel bank data bus monitoring scheme automatically determines if a channel unit connector slot is occupied, without having to gain physical access to the interior of the channel bank cabinet and inspect the channel bank's backplane slot positions. To this end, for a respective channel unit connector slot the channel bank's transmit data bus, which is initially pulled high via a pull-up resistor, is monitored for an all `1`s state. If the data on the bus is not all `1`s, then it is inferred that a channel unit is installed. If an all `1`s state is not detected, then, during the next time slot for that channel unit, the bus is decoupled from the pull-up resistor and coupled instead to a `soft` pull-down resistor. If the data on the bus is now all `0`s, it is inferred that the previously read all `1`s condition was due to the fact that no channel unit is installed, and the channel unit connector slot is declared as empty. However, if the data on the TDATA bus is not all `0`s, it is inferred that the previously read all `1`s condition was actual data asserted by an installed channel unit, and the channel unit connector slot is declared as occupied.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.