IRIG-B do not need any configuration but the proper hardware must be selected. You need the model with serial port and for Easergy P3 standard the cable REL52826 (VX083) in order to connect the IRIG-B signal. For Easergy P3 advanced you need the communication card with serial port in slot 9 in order to connect the IRIG-B signal to pins 4 and 5.
Easergy P3 support unmodulated mode 003 and 004
Easergy P3 support unmodulated mode 003 and 004