Following VCFMW 18, one of the items on my list of improvements was to create a common subscriber network interface device of sorts. The Shady Rate Interface is what I ultimately came up with.
The basic design intent was simple. I wanted:
The general structure of the device consists of a few blocks interconnecting the INPUT jack, the THRU jack, and the OUTPUT jacks. Each jack is an 8P jack following TIA568A wiring, that is:
The jacks were specifically selected to be ones which mechanically support plugging a 6P plug, if desired. The board also has dual footprints, allowing use of true 6P plugs if desired.
Between the INPUT and the THRU, there is a 2x8 polarity reversing jumper field. These jumpers are an arrangement that allows three possible states for each pair:
The diagram shows the arrangement of the four pairs in the jumper field. It also illustrates the jumper arrangements as horizontal for normal polarity and vertical for reversed polarity.
An identical polarity reversing arrangement is also used between the INPUT jack and the cross-point fields for the OUTPUT jacks.
Each of the cross-point jumper fields allows mapping any one of the four input pairs to each output jack pair. The pin arrangement was reduced and optimized to allow this with a minimal number of pins using a clever arrangement.
Unfortunately, clever arrangements are often harder to understand, so some explanation is required.
In the jumper pin field, the four possible input pairs appear interleaved with the 4 possible output pairs. The arrangement is designed such that each input pair has adjacency to each of the output pairs. In this way, a single pin jumper between two adjacent pins has the potential to map any input pair to any output pair.
In order to achieve the adjacency requirement, some pins must be repeated twice. Additionally, each field of 12 pins as shown only covers either tip or ring, and there are duplicate tip and ring pin fields for each output jack. For normal applications, the tip and ring pin fields will use identical jumpering.
All of the possible individual jumper positions are outlined here for clarity.
In order to assemble the Shady Rate Interfaces in the quantity I needed for VCFMW, I bought a solder pot. My process is outlined in this video on youtube.
To attach the acrylic covers, the hardware stack is as follows, starting from the bottom and working up:
On Rev B of the PCBA, the nuts that sit near the PCB must be oriented such that the flat is parallel to the short edge of the board and the cover. This is due to a mistake I made thinking that 1/4" nuts were the common ones, and designing the board without enough clearance to support a 5/16" nut.
The design files are available for reference only at this time. No rights are granted to anyone who possesses the design files. To discuss licensing, please contact me.
All of the CAD and other information (aside from what's on this page) are in the design file package.
As mentioned earlier, on Rev B of the PCBA, the nuts that sit near the PCB must be oriented such that the flat is parallel to the short edge of the board and the cover. This is due to a mistake I made thinking that 1/4" nuts were the common ones, and designing the board without enough clearance to support a 5/16" nut.
Additionally, the laser-cut acrylic covers need larger holes because lasercutting does not cut holes with straight walls (they can end up conical or slanted).