- 4 interfaces with RJ45 plugs (uses a combined 4-block of RJ45 I found in an old switch. Standard distance would need to pull these apart 50 thou/mil)
- TTL compatible with 3.3V, so can interface with Rasberry Pi or Beaglebone Black.
- Creates RS232 line voltages from a single 3.3V supply.
- Uses a SP3232E, essentially a MAX232 compatible chip for 3.3V supply voltage and only 100nF capcitors needed.
- Allows to power external terminals on Line 7 and 8 (see
../terminalfor details) - FYI M3 mounting holes are 18mmx64mm apart.
Learnings from first board, possibly add to second revision
- It would be useful to have a four line voltage/ground connector, directly compatible with the corresponding 4-pin connector on the terminal side.
- Silk-screen marking RX/TX
- 3-Pin connector for 12v: [GND-12v-GND] to allow turn-agnostic plug.
- Possibe protection circuit: reverse polarity protection diode; PTC fuse
- optional 12V power LED ? Maybe optional 3.3V power LED
- RX/TX LEDs. Check connection of RJ45 plugs, some have built-in LEDs (usually to indicate Ethernet 100Mbps/1Gbps), would be cool to re-use these. Also optional space for discrete diodes.
- All LEDs: also provide pads on the bottom of the board if that is the part visible.