Review on 🔌 Industrial Electrical RS232 Serial Cable Communication by DTECH by Justin Gerrero

Description says: Connected as a 9-pin serial zero modem connector cable, where 2-3 lines are sewn together (only TX/RX data lines and signal ground lines are connected); the standard is shielded with aluminum foil And it is true that pins 2 and 3 are optionally bridged, but it is not true that only TX and RX are grounded. All other pins are connected directly, which means that if you connect it to another DCE device, both sides will try to drive the same lines. Even if you don't have a handshake, you can still get into trouble if the two sides fight each other. The manufacturer's solution would be to either cross (pins 4 and 6) and (pins 7 and 8) or, as the description says, assume there is no handshake and leave all other pins unconnected. That means having only 3 wires in the cable.