This is in continuation to my previous post, adding portion of the schematic diagram.
The i coupler used here to isolate one of the OEM device from main circuit. OEM device talks to us at 9600 Baud rate by using RS232 protocol.
There is a RS232 level translator used to convert RS232 levels to TTL/CMOS levels.
ADUM1201 Pin # 6 is host side (TTL/CMOS) input (Host RXD) (wafeform not taken)
ADUM1201 Pin # 7 is host side (TTL/CMOS) output(host TXD) (waveform # 2, in light blue color)
ADUM1201 Pin # 3 OEM device side (TTL/CMOS) output (OEM TXD) (waveform # 4 in Green color)
ADUM1201 Pin # 2 OEM device side (TTL/CMOS) input (OEM RXD) (waveform # 1 in Dark Blue color)
PL click on the waveform graphic for viewing in zoom mode, graphic shall pop up automatic.
Hope the inputs are sufficient for your analysis.
Thanks and Regards,