Dual rs232 DB9 adapter "plank"

Development
21

I NEED this new rev when it comes out. :drooling_face:

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22

I like the idea of breakout pin headers.

How would that look like in detail?

Version 1: one single row of 9 pin headers on each of the two DB-9 connectors.

This could be used like this:

  • The device you want to connect to uses some other kind of connector than DB-9 and you want to connect a breakout cable to that connector. Hooking up pin headers is easier than making a custom DB-9 adapter
  • You need to supply static signals for things like DSR, DCD, RI for example in a null-modem style connection. You now use jumper wires to connect for example DCD, DSR and DTR together to make device detection work.
  • You need fully software controllable signals for DCD, DSR, DTR, RI, for example because they are (mis-)used to implement some reset/bootloader logic. You now use the second RS232 interface on the plank to control these signals by connecting for example TX of the second RS232 interface to DTR of the first with a jumper wire
  • If the device you want to connect to uses a non-standard DB-9 pinout you are out of luck and need an additional breakout adapter/cable

Version 2: dual row 9 pin headers and 9 jumpers on each of the two DB-9 connectors

  • By default all 9 jumpers are set, bridging the RS232 interface and DB-9 connector in the default pinout
  • If you encounter a non-default pinout you remove the jumpers and can then manually reroute the pinout with jumper wires

I’m not sure how often non-default pinouts are in practice and if it is worth the extra space, solder joints and parts for version 2.

Another idea: I have often seen that manufacturers are running RS232 over RJ45. The most common example of this is the Cisco-style pinout that is very common on professional network equipment like switches, routers, PBXes,… You could add 2 RJ45 sockets with the Cisco-pinout to the plank for this, wired in parallel to the two DB-9 connectors.

But with RJ45 I have seen different pinouts than Cisco-style too. The most famous is probably older APC UPSes that had several different pinouts and they sold various totally overpriced adapters for them. But I remember updating a PBX with a hand-made RJ45-RS232 adapter cable one time. So for RJ45 the version 2 with jumpers and fully reconfigurable pinout would make more sense.

@ian now you get to decide where useful features end and feature-creep begins…

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