I have 2 USB, 2 Ehthernet and 2 RS232 connectors on the PCB. USB conns are one side, Ethernet conns on the 2nd side and RS232 on the 3rd side of the board. All are through hole connectors and on top layer with separate chassis ground area on each side for connectors shields. So I have three chassis ground islands on th board for three sets of these connectors. If we have to connect the chassis ground to the signal ground through 1M Resistor and 1nf/2KV capacitor, which of the following is better and why.
1) keep the 3 chassis ground areas separate and connect each of them to the signal ground through 1M Res and 1nf/2KV cap. In this case there will be 3 pairs of 1M and 1nf in parallel. Is this an issue? 2) Have one chassis ground covering all three sides of the board and connect to the signal ground with 1M Res and 1nf/2KV cap. 3) What is the better place to connect the chassis ground and signal ground? Is it at the power supply return? 4) I have seen one reference design on the net with power supply return and connector shields connected together in a copper area and this copper area connected to the signal ground through a ferrite bead.It is an 8 layer board with two signal ground planes and chassis ground on all layers beneath the connectors stitched together at multiple places with vias.
Thanks mark