Both the Relay and Viby pods have a 12V jack on the back panel.
Normally these pods get their power via the 4 wire RJ-11, so you can
ignore this jack. However you can supply power instead via the jack as
an option. You might want to do this if your relays/vibrators are very
power hungry or the RJ-11 cable is quite long with small gauge wire.
eStim pods use very little power from the 12 volts supply, so the 12
volt jack would never be needed and is omitted.