NETGEAR GS110T Detailed Features
The two SFP connectors on the right hand side of the front panel have small plastic plugs installed at the factory, presumably to keep dust out. Although they are intended to ultimately interface with fiber optic cables for long cable runs, the optics (LEDs, lenses, etc) are completely contained in the adapter plug. The interface from the GS110T to the adaptor plug is 100% electrical, so I’m not sure what the dust covers are protecting.
Once the top cover is removed, most of the construction details are laid bare. There’s one printed circuit board, which covers the entire width and depth of the unit, and all the components, functions, lights, connectors are integrated on the one PCB. The board is held down with screws to standoffs on the bottom plate and is very firmly mounted. Only one of the chips on the PCB has a heatsink attached to it, and there are very few integrated circuits on the board itself, indicating a high level of integration into the main chip. The switches with Power-Over-Ethernet (POE) have a few more components added into the mix, as the heavy current delivery demands are not yet integrated into high-end switching devices. The passive heat transfer from the main IC is aided by a silicone pad sandwiched between the top cover and the aluminum heatsink. Part of this design is meant to transfer heat to a bigger radiating area, and it’s also intended to maintain pressure on the heatsink to keep it firmly planted on the chip it serves. This is one of the clear lessons in CPU cooling we’ve learned at Benchmark Reviews, that consistent, firm pressure at the heatsink/chip interface is a key element in heat transfer performance.
Looking at the bottom of the PCB, once it’s removed from the case, we see a couple of insulating components. The larger sheet of thick insulating plastic sheet is kept in place by the four mounting screws which pass through it, and another silicone thermal pad, that you can’t see yet. The smaller, round domed components are specialized covers for the slotted screw holes on the bottom plate, which are used for wall mounting. Two of the four stainless steel standoffs that the PCB sits on are visible at the far end of the chassis.
The PCB has a very simple overall layout. Power comes in at the lower right, and is filtered and regulated there. All the I/O is along the top edge of the board, including the manual switches and indicators. The main switching IC in the center is surrounded by its support chips. Just to the right, partially hidden under the heatsink is the FLASH memory where all the configuration settings are stored. To the left of the main IC is the DDR 400 DRAM, and located in the ideal spot, between the switch IC and the Ethernet connectors, are the pulse transformers that isolate the signals and provide the proper terminating impedance.
Directly below the main IC, which does duty as a Switch, CPU, and x8 PHY, there are a hundred or so surface mount devices soldered to the PCB. Just like in a video card, where the area around the GPU gets hotter than the rest of the card, backside cooling in this spot is an effective way to pull heat out of the assembly. In this case, NETGEAR used another of the silicone thermal pads to both even out the temperature on the PCB and transfer some heat out to the bottom surface of the metal case.
Now that we can get a good look at the PCB, let’s dig down one more later, to the chip level. The next section is called Technology Details…