If you are communicating with the modem using RealPort (COM or tty port), then the profile should be set to RealPort.
Does your modem have dip switches?
Sportster modems should be set initially for
DIP switches 3,7, and 8 down (The rest UP):
*Switch 3 Down is display result codes
*Switch 7 Down is Load factory defaults
*Switch 8 Down is Smart Mode
Courier modems should be set initially for
DIP switches 3 and 8 ON (The rest OFF):
*Switch 3 On Display Result Codes
*Switch 8 On Enable AT Command Set
If you connect to the port are you able to send AT commands and see a response? If so, you might need to configure the DTE port speed by connecting to the port and issuing AT&W, for Courier models the command sequence to set the DTE speed is: AT&B1&W.
If you are unable to send AT commands to the modem and get a response, you will want to double check your cabling:
Digi does sell modtap adapters that can be used with straight through RJ45 cabling: