Serial port pinout for INOR loop transmitter

[RadioRon]

I'm looking for pinout and interface information for the serial port used in the INOR IPAQ Hplus current loop transmitter. I have this transmitter, but I don't have the correct programming cable and need to make one up, but I don't know which pin is which and I don't know what voltage levels to expect. Does anyone out there have any details that would be helpful?

If it might be helpful, here is the datasheet for the transmitter:

https://www.electro-tech-online.com/custompdfs/2007/01/IPAQ-HPlus20-HXPlus20Datasheet.pdf