Electricity: electrical systems and devices – Safety and protection of systems and devices – High voltage dissipation
Reexamination Certificate
2000-03-28
2002-06-04
Tso, Edward H. (Department: 2836)
Electricity: electrical systems and devices
Safety and protection of systems and devices
High voltage dissipation
Reexamination Certificate
active
06400548
ABSTRACT:
BACKGROUND
The invention relates to an Electromagnetic Induction (EMI) shield.
EMI poses a serious design challenge to network component design, particularly as supported data throughput rates meet and exceed those specified by the well-known Fast Ethernet (100 Mb/s) and Gigabit Ethernet (1000 Mb/s) standards. EMI is especially problematic where, as a cost-savings effort, “unshielded” cabling and connectors are used to communicate signals that indicate information for high speed local area network (LAN) traffic.
Due to the signal distortion that EMI introduces, EMI can cause data loss within and about the network component exhibiting the same, and can interfere with or otherwise adversely affect the operation of other electronic devices adjacent thereto. Accordingly, the FCC of the United States, for example, has promulgated a FCC part 15 subpart A, class A standard that defines the maximum acceptable radiated EMI emissions for electronic devices falling under class A classification. Compliance with this or a similar standard such as the CISPR 22 class A standard, meaning that exhibited EMI emissions for a given electronic device such as a network component will not exceed the defined class A threshold, is desirable in order to maximize potential placement and use of the subject network component within a network, and therefore, maximize its flexibility and value to potential customers. In the past, such network components have incorporated conventional shielded connections to keep radiated EMI to a minimum to comply to these standards.
However, as alluded to above, cost considerations have forced network component designers to forgo shielded connections where possible to keep their components price competitive and compatible with the broadcast array of connection and interfacing gear. Therefore, alternative ways of reducing EMI must be explored.
SUMMARY
In general, according to one embodiment of the invention, a conductive shield includes a first portion to contact and establish an electrical connection with a modular connector and a second portion. The second portion electrically couples the first portion to communicate with ground of a circuit board to shunt EMI from the modular connector.
In general, according to another embodiment of the invention, a system includes a circuit board, a modular connector and an EMI shield. The circuit board includes a groundplane and a groundpad that is electrically coupled to the groundplane. The EMI shield includes a first portion to contact and establish an electrical connection with the modular connector. Another portion of the EMI shield contacts the groundpad to electrically couple the first portion to the groundpad to shunt EMI from the modular connector.
The advantages of the above-described arrangements may include one or more of the following. These arrangements may provide a cost effective way to shield EMI from a modular connector, such as a network connector, for example. These arrangements may facilitate assembly of modular connectors onto circuit boards. EMI emissions may be reduced. Assembly time may be minimized.
Other features and advantages will become apparent from the following description, from the drawings and from the claims.
REFERENCES:
patent: 4772212 (1988-09-01), Sotolongo
patent: 6196879 (2001-03-01), Hess et al.
patent: 6217351 (2001-04-01), Fung et al.
patent: 6250964 (2001-06-01), Fair et al.
Nortel Networks Corporation
Tibbits Pia
Trop Pruner & Hu P.C.
Tso Edward H.
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