communications wiring diagrams

fyi,  this is for a EG4 wall mount indoor 280ah battery

I don't know if this helps any but here is a DOC from EG4:

And an image from Signature Solar:

thanks.  i saw that but they don't list the gnd pin, the voltage levels, or the reference direction for TX/RX.  RS232 is speced at +/- 12 but everyone misuses the terminiology.  They apparently use a microchip pic processor in this unit which will only tolerate 0 to +5 without a seperate driver chip.  just want to verify all the parameters before i brick this guys battery. 

just saw the diagram you posted,  hadn't seen that before.  makes it really interesting.  some pic processors take USB directly so maybe don't need a converter but then its not really RS232.  gotta study that diagram and see if there is a converter in the USB pod. thx.

hey,  that really helped.  they have a FT232 USB to UART chip in that pod so the outputs are serial not USB.  the pin number question is solved.  now i just need to resolve the levels and whether the RXD on RJ45 is the TXD on the pod or they are swapped.  the diagram doesn't give TXD/RXD at the Pod side or input connector side, just the RJ45 connection

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if anyone has that cable and can throw a voltmeter across RXD(1) and ground(8) and TXD(2) and ground on the RJ45 and post the levels that would solve the whole problem.  I'll post a complete DIY cable diagram from amazon parts once this works for folks that get stuck like me.

that picture you sent may have the information, but the connector diagram on the lower left is too blurry to read when i blow it up.  You don't have a URL for the original pic on sig solar site do you?  having trouble finding it.

they use a ZT213 chip (i can read that part of picture) which is a drop in replacement for the old MAX chips i used to use so the outputs are +/- 12V synthesized from the 5V on USB.  Thanks Joel,  that was really helpful.  I should be able to figure out the pin swapping now.  thx.

@kubota Here is the link to the cable, it is the second Pic

EG4 RS232 Firmware Update Cable - LL - Signature Solar

well that was right in plain sight. 

still not readable but i can figure it out with a voltmeter.   a std amazon usb to 232, cut off the db9, splice on a rj45, i should be in business. 

every place i looked it's second week of january to get one.  can't delay this install that long.  off to the shop.  thx again fir all your help. 

got the parts, made the cable, tested offline.  complies with all RS232 params.

before i hooked it up tested voltage levels on output of battery.

instead of -12 at idle on the TxD line,  the mark level appears to be +5 which is ttl serial, not rs232. 

so now i am afriad to hook up a true rs232 until i can verify levels and figure out if i need to invert the data stream and shift the levels from the RS232 IEEE standard.  this is just getting very frustrating.  why don't they send the cable with the unit if its required to update the unit before powering up or publish the needed data for techs

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@kubota And it should be posted what the interface is.... RS232 means RS232 standard +/- 12V(15V sometimes)and UART tells it's love voltage but also needs to the voltage specified of 3.3V or 5V.  They posted TxD and RxD which is standard serial( not CAN, not RS485 ) but again, they should have posted voltage data.  Try a LuxPower site if it's an EG4 18KPV inverter since they are the same as the LuxPower 12K.

finally got an official update cable on the way.  i'll measure output volts and mark/space states and post back here for anyone else in future this desperate to finish an install.