Sounds like parameters.
Hopefully you had a accurate options file to enable Reader/Puncher interface and its just a matter of getting the comms parameters set.
There are a few involved with serial communication. They need to be set to match your DNC software.
A parameter manual would help.
Some settings are found on the "Settings" screen as well as in parameters (ISO, Channel, and TVC).
The most basic Parameters associated with communication.
0000 ISO,TVC
0020 Device selection (0 = RS232 port 1. most common setting)
0101 SB2,NFD, ASI
0102 Device type (4 = RS232 DC1 to DC4 not used. Most common setting)
0103 Baud rate (must be set to match PC setting)