I have a fully operational new system but currently without monitoring.
Multiplus 2 48v, BMV 700, automation system
The bmv has a 4 pin serial port on the rear.
5v, Rx, Tx, Gnd.
I have the victron cable 9pin rs232 to the BMV
In the said cable there is circuitry in the 9 pin end, the other end is sealed. see photo.
1; Are the electronics in the lead converting VE bus signals to RS232?
2; Is the output from the BMV’s Rx, Tx, & Gnd standard RS232 protocol or proprietary and only RS232 after the electronics?
3; Does pin 1 on the BMV need 5v or is it supplying 5v?
4; Is the Gnd common to signal & the 5v line?