If you make your own RS-232 cable, be sure to check for the correct pin-out. For years, the RJ11/DB9 adapters were color coded and all were the same. I ran into one recently that was miswired, with the color coded wires internally connected incorrectly. I've also had cables go flakey, as I wrote in a recent blog:
Early version MultiRangers came with P770 configured to code 1 for Dolphin.
Recent MultiRangers now come with P770 default to code 3 for Modbus for use with PDM. (I do not know the date when the switch-over occurred)
If you're running Dolphin software, P770 needs to be code 1.
The word format (8 bits, no parity, 1 stop bit) is the same for PDM or Dolphin. Baud rate has to match that configured in PDM, but Dolphin defaults to 115k.
There are two serial ports, the RJ-11 RS-232 port and the screw terminal RS-485 port.
The RF-11 RS-232 port is index 1.
The screw terminal RS-485 port is index 2.
Each index can be independently configured, one for Dolphin, one for Modbus (PDM), but whichever port you connect to needs to be configured properly.
Be sure that serial port on your PC is available and has not been grabbed by some other application or service. Some industrial communication application (read that as PLC comm services, like RSLinx) apps/services grab and do not release the serial port. If you can't do a loopback with hyperterminal, the port is not free.
Chook: bottom on page 2 of your document,
P770 : 1 << Port Protocol Modbus RTU >>
P771 : 1 << Network Address >>
the P770 should be: P770: 1 << Dolphin >>